21174431638 has 8 divisors (see below), whose sum is σ = 32076119520. Its totient is φ = 10482391800.

The previous prime is 21174431561. The next prime is 21174431647. The reversal of 21174431638 is 83613447112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 21174431638.

It is a congruent number.

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, 52411758 + ... + 52412161.

It is an arithmetic number, because the mean of its divisors is an integer number (4009514940).

Almost surely, 2^21174431638 is an apocalyptic number.

21174431638 is a deficient number, since it is larger than the sum of its proper divisors (10901687882).

21174431638 is a wasteful number, since it uses less digits than its factorization.

21174431638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104824022.

The product of its digits is 96768, while the sum is 40.

The spelling of 21174431638 in words is "twenty-one billion, one hundred seventy-four million, four hundred thirty-one thousand, six hundred thirty-eight".