21957368285161 has 3 divisors (see below), whose sum is σ = 21957372971031. Its totient is φ = 21957363599292.

The previous prime is 21957368285143. The next prime is 21957368285213. The reversal of 21957368285161 is 16158286375912.

The square root of 21957368285161 is 4685869.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 12935394889561 + 9021973395600 = 3596581^2 + 3003660^2 .

It is not a de Polignac number, because 21957368285161 - 2¹⁹ = 21957367760873 is a prime.

It is a super-2 number, since 2×21957368285161² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21957368285093 and 21957368285102.

It is not an unprimeable number, because it can be changed into a prime (21957368285761) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2342935 + ... + 7028803.

It is an arithmetic number, because the mean of its divisors is an integer number (7319124323677).

Almost surely, 2^{21957368285161} is an apocalyptic number.

21957368285161 is the 4685869-th square number.

21957368285161 is the 2342935-th centered octagonal number.

It is an amenable number.

21957368285161 is a deficient number, since it is larger than the sum of its proper divisors (4685870).

21957368285161 is an frugal number, since it uses more digits than its factorization.

21957368285161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9371738 (or 4685869 counting only the distinct ones).

The product of its digits is 43545600, while the sum is 64.

The spelling of 21957368285161 in words is "twenty-one trillion, nine hundred fifty-seven billion, three hundred sixty-eight million, two hundred eighty-five thousand, one hundred sixty-one".