20891963 has 16 divisors (see below), whose sum is σ = 23639040. Its totient is φ = 18345600.

The previous prime is 20891947. The next prime is 20891971. The reversal of 20891963 is 36919802.

It is a cyclic number.

It is not a de Polignac number, because 20891963 - 2⁴ = 20891947 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20891933) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22478 + ... + 23388.

It is an arithmetic number, because the mean of its divisors is an integer number (1477440).

Almost surely, 2^20891963 is an apocalyptic number.

20891963 is a deficient number, since it is larger than the sum of its proper divisors (2747077).

20891963 is a wasteful number, since it uses less digits than its factorization.

20891963 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1018.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 20891963 is about 4570.7726917886. The cubic root of 20891963 is about 275.4184835074.

The spelling of 20891963 in words is "twenty million, eight hundred ninety-one thousand, nine hundred sixty-three".