21039640800 has 72 divisors (see below), whose sum is σ = 68484038616. Its totient is φ = 5610570240.

The previous prime is 21039640789. The next prime is 21039640837. The reversal of 21039640800 is 804693012.

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, 4380859 + ... + 4385658.

It is an arithmetic number, because the mean of its divisors is an integer number (951167203).

Almost surely, 2^21039640800 is an apocalyptic number.

21039640800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21039640800 is an abundant number, since it is smaller than the sum of its proper divisors (47444397816).

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

21039640800 is a wasteful number, since it uses less digits than its factorization.

21039640800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8766540 (or 8766527 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The spelling of 21039640800 in words is "twenty-one billion, thirty-nine million, six hundred forty thousand, eight hundred".