21017544172 has 24 divisors (see below), whose sum is σ = 37330386912. Its totient is φ = 10352073600.

The previous prime is 21017544169. The next prime is 21017544221. The reversal of 21017544172 is 27144571012.

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 7 ways as a sum of consecutive naturals, for example, 195897 + ... + 283567.

It is an arithmetic number, because the mean of its divisors is an integer number (1555432788).

Almost surely, 2^21017544172 is an apocalyptic number.

It is an amenable number.

21017544172 is a deficient number, since it is larger than the sum of its proper divisors (16312842740).

21017544172 is a wasteful number, since it uses less digits than its factorization.

21017544172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88569 (or 88567 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 34.

The spelling of 21017544172 in words is "twenty-one billion, seventeen million, five hundred forty-four thousand, one hundred seventy-two".