20591961 has 16 divisors (see below), whose sum is σ = 29688960. Its totient is φ = 12620160.

The previous prime is 20591939. The next prime is 20591971. The reversal of 20591961 is 16919502.

It is not a de Polignac number, because 20591961 - 2⁶ = 20591897 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20591911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10020 + ... + 11898.

It is an arithmetic number, because the mean of its divisors is an integer number (1855560).

Almost surely, 2^20591961 is an apocalyptic number.

It is an amenable number.

20591961 is a deficient number, since it is larger than the sum of its proper divisors (9096999).

20591961 is a wasteful number, since it uses less digits than its factorization.

20591961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2176.

The product of its (nonzero) digits is 4860, while the sum is 33.

The square root of 20591961 is about 4537.8365990855. The cubic root of 20591961 is about 274.0938149988.

The spelling of 20591961 in words is "twenty million, five hundred ninety-one thousand, nine hundred sixty-one".