21907621361 has 4 divisors (see below), whose sum is σ = 22153774500. Its totient is φ = 21661468224.

The previous prime is 21907621327. The next prime is 21907621363. The reversal of 21907621361 is 16312670912.

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 3415701136 + 18491920225 = 58444^2 + 135985^2 .

It is a cyclic number.

It is not a de Polignac number, because 21907621361 - 2²² = 21903427057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21907621363) 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 3 ways as a sum of consecutive naturals, for example, 123076436 + ... + 123076613.

It is an arithmetic number, because the mean of its divisors is an integer number (5538443625).

Almost surely, 2^21907621361 is an apocalyptic number.

It is an amenable number.

21907621361 is a deficient number, since it is larger than the sum of its proper divisors (246153139).

21907621361 is an equidigital number, since it uses as much as digits as its factorization.

21907621361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 246153138.

The product of its (nonzero) digits is 27216, while the sum is 38.

The spelling of 21907621361 in words is "twenty-one billion, nine hundred seven million, six hundred twenty-one thousand, three hundred sixty-one".