21691869192 has 72 divisors (see below), whose sum is σ = 68340466350. Its totient is φ = 6197675904.

The previous prime is 21691869187. The next prime is 21691869223. The reversal of 21691869192 is 29196819612.

It can be written as a sum of positive squares in only one way, i.e., 17759826756 + 3932042436 = 133266^2 + 62706^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 3070717 + ... + 3077772.

Almost surely, 2^21691869192 is an apocalyptic number.

It is an amenable number.

21691869192 is an abundant number, since it is smaller than the sum of its proper divisors (46648597158).

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

21691869192 is a wasteful number, since it uses less digits than its factorization.

21691869192 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6148515 (or 6148501 counting only the distinct ones).

The product of its digits is 839808, while the sum is 54.

The spelling of 21691869192 in words is "twenty-one billion, six hundred ninety-one million, eight hundred sixty-nine thousand, one hundred ninety-two".