21278763800 has 48 divisors (see below), whose sum is σ = 56540718960. Its totient is φ = 7295575680.

The previous prime is 21278763791. The next prime is 21278763827. The reversal of 21278763800 is 836787212.

It is a happy number.

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, 7598159 + ... + 7600958.

It is an arithmetic number, because the mean of its divisors is an integer number (1177931645).

Almost surely, 2^21278763800 is an apocalyptic number.

21278763800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21278763800 is an abundant number, since it is smaller than the sum of its proper divisors (35261955160).

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

21278763800 is a wasteful number, since it uses less digits than its factorization.

21278763800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15199140 (or 15199131 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 44.

The spelling of 21278763800 in words is "twenty-one billion, two hundred seventy-eight million, seven hundred sixty-three thousand, eight hundred".