21995639660 has 12 divisors (see below), whose sum is σ = 46190843328. Its totient is φ = 8798255856.

The previous prime is 21995639623. The next prime is 21995639723. The reversal of 21995639660 is 6693659912.

It is a junction number, because it is equal to n+sod(n) for n = 21995639596 and 21995639605.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 549890972 + ... + 549891011.

It is an arithmetic number, because the mean of its divisors is an integer number (3849236944).

Almost surely, 2^21995639660 is an apocalyptic number.

21995639660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21995639660 is an abundant number, since it is smaller than the sum of its proper divisors (24195203668).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21995639660 is a wasteful number, since it uses less digits than its factorization.

21995639660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1099781992 (or 1099781990 counting only the distinct ones).

The product of its (nonzero) digits is 4723920, while the sum is 56.

The spelling of 21995639660 in words is "twenty-one billion, nine hundred ninety-five million, six hundred thirty-nine thousand, six hundred sixty".