21131968850 has 12 divisors (see below), whose sum is σ = 39305462154. Its totient is φ = 8452787520.

The previous prime is 21131968789. The next prime is 21131968909. The reversal of 21131968850 is 5886913112.

It can be written as a sum of positive squares in 3 ways, for example, as 19239631849 + 1892337001 = 138707^2 + 43501^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 211319639 + ... + 211319738.

Almost surely, 2^21131968850 is an apocalyptic number.

21131968850 is a deficient number, since it is larger than the sum of its proper divisors (18173493304).

21131968850 is a wasteful number, since it uses less digits than its factorization.

21131968850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 422639389 (or 422639384 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 44.

The spelling of 21131968850 in words is "twenty-one billion, one hundred thirty-one million, nine hundred sixty-eight thousand, eight hundred fifty".