21064432916 has 48 divisors (see below), whose sum is σ = 40186460160. Its totient is φ = 9624238560.

The previous prime is 21064432901. The next prime is 21064432951. The reversal of 21064432916 is 61923446012.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a self number, because there is not a number n which added to its sum of digits gives 21064432916.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 708731 + ... + 737853.

It is an arithmetic number, because the mean of its divisors is an integer number (837217920).

Almost surely, 2^21064432916 is an apocalyptic number.

It is an amenable number.

21064432916 is a deficient number, since it is larger than the sum of its proper divisors (19122027244).

21064432916 is a wasteful number, since it uses less digits than its factorization.

21064432916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29484 (or 29482 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 38.

Adding to 21064432916 its reverse (61923446012), we get a palindrome (82987878928).

The spelling of 21064432916 in words is "twenty-one billion, sixty-four million, four hundred thirty-two thousand, nine hundred sixteen".