21221364340465 has 16 divisors (see below), whose sum is σ = 26288153127936. Its totient is φ = 16428791016000.

The previous prime is 21221364340457. The next prime is 21221364340493. The reversal of 21221364340465 is 56404346312212.

It is not a de Polignac number, because 21221364340465 - 2³ = 21221364340457 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1216515 + ... + 6627415.

It is an arithmetic number, because the mean of its divisors is an integer number (1643009570496).

Almost surely, 2^{21221364340465} is an apocalyptic number.

It is an amenable number.

21221364340465 is a deficient number, since it is larger than the sum of its proper divisors (5066788787471).

21221364340465 is a wasteful number, since it uses less digits than its factorization.

21221364340465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5436240.

The product of its (nonzero) digits is 829440, while the sum is 43.

The spelling of 21221364340465 in words is "twenty-one trillion, two hundred twenty-one billion, three hundred sixty-four million, three hundred forty thousand, four hundred sixty-five".