21661707151767 has 64 divisors (see below), whose sum is σ = 32376206131200. Its totient is φ = 12802336727040.

The previous prime is 21661707151751. The next prime is 21661707151793. The reversal of 21661707151767 is 76715170716612.

It is not a de Polignac number, because 21661707151767 - 2⁴ = 21661707151751 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661707153767) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 124349034 + ... + 124523112.

It is an arithmetic number, because the mean of its divisors is an integer number (505878220800).

Almost surely, 2^{21661707151767} is an apocalyptic number.

21661707151767 is a deficient number, since it is larger than the sum of its proper divisors (10714498979433).

21661707151767 is a wasteful number, since it uses less digits than its factorization.

21661707151767 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174856.

The product of its (nonzero) digits is 5186160, while the sum is 57.

The spelling of 21661707151767 in words is "twenty-one trillion, six hundred sixty-one billion, seven hundred seven million, one hundred fifty-one thousand, seven hundred sixty-seven".