21373873812 has 48 divisors (see below), whose sum is σ = 55651639680. Its totient is φ = 7094038464.

The previous prime is 21373873789. The next prime is 21373873837. The reversal of 21373873812 is 21837837312.

It is a happy number.

It is a super-2 number, since 2×21373873812² (a number of 21 digits) contains 22 as substring.

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, 399528 + ... + 449855.

It is an arithmetic number, because the mean of its divisors is an integer number (1159409160).

Almost surely, 2^21373873812 is an apocalyptic number.

It is an amenable number.

21373873812 is an abundant number, since it is smaller than the sum of its proper divisors (34277765868).

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

21373873812 is a wasteful number, since it uses less digits than its factorization.

21373873812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 849629 (or 849621 counting only the distinct ones).

The product of its digits is 338688, while the sum is 45.

It can be divided in two parts, 213 and 73873812, that added together give a square (73874025 = 8595²).

The spelling of 21373873812 in words is "twenty-one billion, three hundred seventy-three million, eight hundred seventy-three thousand, eight hundred twelve".