20997996 has 12 divisors (see below), whose sum is σ = 48995352. Its totient is φ = 6999328.

The previous prime is 20997989. The next prime is 20998007. The reversal of 20997996 is 69979902.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 874905 + ... + 874928.

It is an arithmetic number, because the mean of its divisors is an integer number (4082946).

Almost surely, 2^20997996 is an apocalyptic number.

It is an amenable number.

20997996 is an abundant number, since it is smaller than the sum of its proper divisors (27997356).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20997996 is a wasteful number, since it uses less digits than its factorization.

20997996 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1749840 (or 1749838 counting only the distinct ones).

The product of its (nonzero) digits is 551124, while the sum is 51.

The square root of 20997996 is about 4582.3570354131. The cubic root of 20997996 is about 275.8836413525.

The spelling of 20997996 in words is "twenty million, nine hundred ninety-seven thousand, nine hundred ninety-six".