21516783694 has 16 divisors (see below), whose sum is σ = 36931528800. Its totient is φ = 9210075264.

The previous prime is 21516783679. The next prime is 21516783709. The reversal of 21516783694 is 49638761512.

It is an interprime number because it is at equal distance from previous prime (21516783679) and next prime (21516783709).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 938559 + ... + 961210.

It is an arithmetic number, because the mean of its divisors is an integer number (2308220550).

Almost surely, 2^21516783694 is an apocalyptic number.

21516783694 is a deficient number, since it is larger than the sum of its proper divisors (15414745106).

21516783694 is a wasteful number, since it uses less digits than its factorization.

21516783694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1900587.

The product of its digits is 2177280, while the sum is 52.

The spelling of 21516783694 in words is "twenty-one billion, five hundred sixteen million, seven hundred eighty-three thousand, six hundred ninety-four".