20991596 has 6 divisors (see below), whose sum is σ = 36735300. Its totient is φ = 10495796.

The previous prime is 20991577. The next prime is 20991601. The reversal of 20991596 is 69519902.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2623946 + ... + 2623953.

It is an arithmetic number, because the mean of its divisors is an integer number (6122550).

Almost surely, 2^20991596 is an apocalyptic number.

It is an amenable number.

20991596 is a deficient number, since it is larger than the sum of its proper divisors (15743704).

20991596 is a wasteful number, since it uses less digits than its factorization.

20991596 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5247903 (or 5247901 counting only the distinct ones).

The product of its (nonzero) digits is 43740, while the sum is 41.

The square root of 20991596 is about 4581.6586516239. The cubic root of 20991596 is about 275.8556095549.

The spelling of 20991596 in words is "twenty million, nine hundred ninety-one thousand, five hundred ninety-six".