20991496 has 8 divisors (see below), whose sum is σ = 39359070. Its totient is φ = 10495744.

The previous prime is 20991493. The next prime is 20991511. The reversal of 20991496 is 69419902.

It can be written as a sum of positive squares in only one way, i.e., 20520900 + 470596 = 4530^2 + 686^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (20991493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1311961 + ... + 1311976.

Almost surely, 2^20991496 is an apocalyptic number.

It is an amenable number.

20991496 is a deficient number, since it is larger than the sum of its proper divisors (18367574).

20991496 is a wasteful number, since it uses less digits than its factorization.

20991496 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2623943 (or 2623939 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 20991496 is about 4581.6477385325. The cubic root of 20991496 is about 275.8551715129.

The spelling of 20991496 in words is "twenty million, nine hundred ninety-one thousand, four hundred ninety-six".