21354206672 has 20 divisors (see below), whose sum is σ = 41395239300. Its totient is φ = 10671564288.

The previous prime is 21354206659. The next prime is 21354206683. The reversal of 21354206672 is 27660245312.

It can be written as a sum of positive squares in 2 ways, for example, as 11241088576 + 10113118096 = 106024^2 + 100564^2 .

It is a congruent number.

It is an unprimeable number.

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, 314297 + ... + 376152.

It is an arithmetic number, because the mean of its divisors is an integer number (2069761965).

Almost surely, 2^21354206672 is an apocalyptic number.

It is an amenable number.

21354206672 is a deficient number, since it is larger than the sum of its proper divisors (20041032628).

21354206672 is a wasteful number, since it uses less digits than its factorization.

21354206672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 692390 (or 692384 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 38.

The spelling of 21354206672 in words is "twenty-one billion, three hundred fifty-four million, two hundred six thousand, six hundred seventy-two".