21553094085961 has 3 divisors (see below), whose sum is σ = 21553098728493. Its totient is φ = 21553089443430.

The previous prime is 21553094085931. The next prime is 21553094086087. The reversal of 21553094085961 is 16958049035512.

It is a happy number.

The square root of 21553094085961 is 4642531.

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 is not a de Polignac number, because 21553094085961 - 2⁹ = 21553094085449 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21553094085896 and 21553094085905.

It is not an unprimeable number, because it can be changed into a prime (21553094085931) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2321266 + ... + 6963796.

It is an arithmetic number, because the mean of its divisors is an integer number (7184366242831).

Almost surely, 2^{21553094085961} is an apocalyptic number.

21553094085961 is the 4642531-st square number.

21553094085961 is the 2321266-th centered octagonal number.

It is an amenable number.

21553094085961 is a deficient number, since it is larger than the sum of its proper divisors (4642532).

21553094085961 is an frugal number, since it uses more digits than its factorization.

21553094085961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9285062 (or 4642531 counting only the distinct ones).

The product of its (nonzero) digits is 11664000, while the sum is 58.

The spelling of 21553094085961 in words is "twenty-one trillion, five hundred fifty-three billion, ninety-four million, eighty-five thousand, nine hundred sixty-one".