21017161772 has 24 divisors (see below), whose sum is σ = 37642529232. Its totient is φ = 10262246400.

The previous prime is 21017161769. The next prime is 21017161813. The reversal of 21017161772 is 27716171012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1382372 + ... + 1397492.

It is an arithmetic number, because the mean of its divisors is an integer number (1568438718).

Almost surely, 2^21017161772 is an apocalyptic number.

It is an amenable number.

21017161772 is a deficient number, since it is larger than the sum of its proper divisors (16625367460).

21017161772 is a wasteful number, since it uses less digits than its factorization.

21017161772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23249 (or 23247 counting only the distinct ones).

The product of its (nonzero) digits is 8232, while the sum is 35.

The spelling of 21017161772 in words is "twenty-one billion, seventeen million, one hundred sixty-one thousand, seven hundred seventy-two".