21661042100502 has 16 divisors (see below), whose sum is σ = 49510953372672. Its totient is φ = 6188869171560.

The previous prime is 21661042100501. The next prime is 21661042100527. The reversal of 21661042100502 is 20500124016612.

It is a self number, because there is not a number n which added to its sum of digits gives 21661042100502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21661042100501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 257869548774 + ... + 257869548857.

It is an arithmetic number, because the mean of its divisors is an integer number (3094434585792).

Almost surely, 2^{21661042100502} is an apocalyptic number.

21661042100502 is an abundant number, since it is smaller than the sum of its proper divisors (27849911272170).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21661042100502 is a wasteful number, since it uses less digits than its factorization.

21661042100502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515739097643.

The product of its (nonzero) digits is 5760, while the sum is 30.

The spelling of 21661042100502 in words is "twenty-one trillion, six hundred sixty-one billion, forty-two million, one hundred thousand, five hundred two".