21641640536 has 16 divisors (see below), whose sum is σ = 40586600040. Its totient is φ = 10818547200.

The previous prime is 21641640533. The next prime is 21641640541. The reversal of 21641640536 is 63504614612.

It is a self number, because there is not a number n which added to its sum of digits gives 21641640536.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21641640533) 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, 243326 + ... + 320141.

Almost surely, 2^21641640536 is an apocalyptic number.

It is an amenable number.

21641640536 is a deficient number, since it is larger than the sum of its proper divisors (18944959504).

21641640536 is a wasteful number, since it uses less digits than its factorization.

21641640536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 568274 (or 568270 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 38.

The spelling of 21641640536 in words is "twenty-one billion, six hundred forty-one million, six hundred forty thousand, five hundred thirty-six".