21100431996 has 72 divisors (see below), whose sum is σ = 61094726784. Its totient is φ = 6015054240.

The previous prime is 21100431973. The next prime is 21100432021. The reversal of 21100431996 is 69913400112.

It is a happy number.

21100431996 is a `hidden beast` number, since 211 + 0 + 0 + 431 + 9 + 9 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 21100431996.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17131 + ... + 206141.

It is an arithmetic number, because the mean of its divisors is an integer number (848537872).

Almost surely, 2^21100431996 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21100431996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30547363392).

21100431996 is an abundant number, since it is smaller than the sum of its proper divisors (39994294788).

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

21100431996 is a wasteful number, since it uses less digits than its factorization.

21100431996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189471 (or 189466 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The spelling of 21100431996 in words is "twenty-one billion, one hundred million, four hundred thirty-one thousand, nine hundred ninety-six".