21366434646 has 24 divisors (see below), whose sum is σ = 46474083864. Its totient is φ = 7094430720.

The previous prime is 21366434587. The next prime is 21366434653. The reversal of 21366434646 is 64643466312.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2304760 + ... + 2314011.

It is an arithmetic number, because the mean of its divisors is an integer number (1936420161).

Almost surely, 2^21366434646 is an apocalyptic number.

21366434646 is an abundant number, since it is smaller than the sum of its proper divisors (25107649218).

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

21366434646 is a wasteful number, since it uses less digits than its factorization.

21366434646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4619036 (or 4619033 counting only the distinct ones).

The product of its digits is 1492992, while the sum is 45.

The spelling of 21366434646 in words is "twenty-one billion, three hundred sixty-six million, four hundred thirty-four thousand, six hundred forty-six".