20960991 has 32 divisors (see below), whose sum is σ = 32563200. Its totient is φ = 13309920.

The previous prime is 20960959. The next prime is 20960999. The reversal of 20960991 is 19906902.

It is not a de Polignac number, because 20960991 - 2⁵ = 20960959 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20960999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 65965 + ... + 66281.

It is an arithmetic number, because the mean of its divisors is an integer number (1017600).

Almost surely, 2^20960991 is an apocalyptic number.

20960991 is a deficient number, since it is larger than the sum of its proper divisors (11602209).

20960991 is a wasteful number, since it uses less digits than its factorization.

20960991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 436 (or 430 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 20960991 is about 4578.3174857146. The cubic root of 20960991 is about 275.7214817951.

The spelling of 20960991 in words is "twenty million, nine hundred sixty thousand, nine hundred ninety-one".