21307952465 has 4 divisors (see below), whose sum is σ = 25569542964. Its totient is φ = 17046361968.

The previous prime is 21307952429. The next prime is 21307952489. The reversal of 21307952465 is 56425970312.

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 10855139344 + 10452813121 = 104188^2 + 102239^2 .

It is a cyclic number.

It is not a de Polignac number, because 21307952465 - 2⁸ = 21307952209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is an unprimeable number.

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, 2130795242 + ... + 2130795251.

It is an arithmetic number, because the mean of its divisors is an integer number (6392385741).

Almost surely, 2^21307952465 is an apocalyptic number.

It is an amenable number.

21307952465 is a deficient number, since it is larger than the sum of its proper divisors (4261590499).

21307952465 is an equidigital number, since it uses as much as digits as its factorization.

21307952465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4261590498.

The product of its (nonzero) digits is 453600, while the sum is 44.

The spelling of 21307952465 in words is "twenty-one billion, three hundred seven million, nine hundred fifty-two thousand, four hundred sixty-five".