21373355816 has 16 divisors (see below), whose sum is σ = 42184255200. Its totient is φ = 10124221104.

The previous prime is 21373355807. The next prime is 21373355819. The reversal of 21373355816 is 61855337312.

It is a Smith number, since the sum of its digits (44) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (21373355819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 70306940 + ... + 70307243.

It is an arithmetic number, because the mean of its divisors is an integer number (2636515950).

Almost surely, 2^21373355816 is an apocalyptic number.

It is an amenable number.

21373355816 is a deficient number, since it is larger than the sum of its proper divisors (20810899384).

21373355816 is a wasteful number, since it uses less digits than its factorization.

21373355816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140614208 (or 140614204 counting only the distinct ones).

The product of its digits is 453600, while the sum is 44.

The spelling of 21373355816 in words is "twenty-one billion, three hundred seventy-three million, three hundred fifty-five thousand, eight hundred sixteen".