21684581798 has 16 divisors (see below), whose sum is σ = 35559860544. Its totient is φ = 9835517160.

The previous prime is 21684581777. The next prime is 21684581827. The reversal of 21684581798 is 89718548612.

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, 1045040 + ... + 1065587.

It is an arithmetic number, because the mean of its divisors is an integer number (2222491284).

Almost surely, 2^21684581798 is an apocalyptic number.

21684581798 is a deficient number, since it is larger than the sum of its proper divisors (13875278746).

21684581798 is a wasteful number, since it uses less digits than its factorization.

21684581798 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2111107.

The product of its digits is 7741440, while the sum is 59.

The spelling of 21684581798 in words is "twenty-one billion, six hundred eighty-four million, five hundred eighty-one thousand, seven hundred ninety-eight".