21065390738 has 32 divisors (see below), whose sum is σ = 37219996800. Its totient is φ = 8753754240.

The previous prime is 21065390711. The next prime is 21065390783. The reversal of 21065390738 is 83709356012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19013 + ... + 206136.

It is an arithmetic number, because the mean of its divisors is an integer number (1163124900).

Almost surely, 2^21065390738 is an apocalyptic number.

21065390738 is a deficient number, since it is larger than the sum of its proper divisors (16154606062).

21065390738 is a wasteful number, since it uses less digits than its factorization.

21065390738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225362.

The product of its (nonzero) digits is 272160, while the sum is 44.

The spelling of 21065390738 in words is "twenty-one billion, sixty-five million, three hundred ninety thousand, seven hundred thirty-eight".