21601746618 has 16 divisors (see below), whose sum is σ = 43206268320. Its totient is φ = 7200119696.

The previous prime is 21601746613. The next prime is 21601746619. The reversal of 21601746618 is 81664710612.

It is a self number, because there is not a number n which added to its sum of digits gives 21601746618.

It is not an unprimeable number, because it can be changed into a prime (21601746613) 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, 6513 + ... + 207956.

It is an arithmetic number, because the mean of its divisors is an integer number (2700391770).

Almost surely, 2^21601746618 is an apocalyptic number.

21601746618 is an abundant number, since it is smaller than the sum of its proper divisors (21604521702).

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

21601746618 is a wasteful number, since it uses less digits than its factorization.

21601746618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231261.

The product of its (nonzero) digits is 96768, while the sum is 42.

The spelling of 21601746618 in words is "twenty-one billion, six hundred one million, seven hundred forty-six thousand, six hundred eighteen".