21655212034663 has 4 divisors (see below), whose sum is σ = 22929048036720. Its totient is φ = 20381376032608.

The previous prime is 21655212034583. The next prime is 21655212034681. The reversal of 21655212034663 is 36643021255612.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21655212034663 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21655212034693) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 636918001003 + ... + 636918001036.

It is an arithmetic number, because the mean of its divisors is an integer number (5732262009180).

Almost surely, 2^{21655212034663} is an apocalyptic number.

21655212034663 is a deficient number, since it is larger than the sum of its proper divisors (1273836002057).

21655212034663 is a wasteful number, since it uses less digits than its factorization.

21655212034663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1273836002056.

The product of its (nonzero) digits is 1555200, while the sum is 46.

The spelling of 21655212034663 in words is "twenty-one trillion, six hundred fifty-five billion, two hundred twelve million, thirty-four thousand, six hundred sixty-three".