21655364603461 has 4 divisors (see below), whose sum is σ = 21655452474124. Its totient is φ = 21655276732800.

The previous prime is 21655364603449. The next prime is 21655364603471. The reversal of 21655364603461 is 16430646355612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10686557140900 + 10968807462561 = 3269030^2 + 3311919^2 .

It is a cyclic number.

It is not a de Polignac number, because 21655364603461 - 2¹¹ = 21655364601413 is a prime.

It is a super-2 number, since 2×21655364603461² (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 = 21655364603399 and 21655364603408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21655364603471) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43564620 + ... + 44058901.

It is an arithmetic number, because the mean of its divisors is an integer number (5413863118531).

Almost surely, 2^{21655364603461} is an apocalyptic number.

It is an amenable number.

21655364603461 is a deficient number, since it is larger than the sum of its proper divisors (87870663).

21655364603461 is an equidigital number, since it uses as much as digits as its factorization.

21655364603461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87870662.

The product of its (nonzero) digits is 9331200, while the sum is 52.

The spelling of 21655364603461 in words is "twenty-one trillion, six hundred fifty-five billion, three hundred sixty-four million, six hundred three thousand, four hundred sixty-one".