20917924 has 6 divisors (see below), whose sum is σ = 36606374. Its totient is φ = 10458960.

The previous prime is 20917891. The next prime is 20917933. The reversal of 20917924 is 42971902.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19980900 + 937024 = 4470^2 + 968^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 20917924.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2614737 + ... + 2614744.

Almost surely, 2^20917924 is an apocalyptic number.

It is an amenable number.

20917924 is a deficient number, since it is larger than the sum of its proper divisors (15688450).

20917924 is a wasteful number, since it uses less digits than its factorization.

20917924 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5229485 (or 5229483 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 20917924 is about 4573.6117019266. The cubic root of 20917924 is about 275.5325174644.

The spelling of 20917924 in words is "twenty million, nine hundred seventeen thousand, nine hundred twenty-four".