20211961 has 24 divisors (see below), whose sum is σ = 25961600. Its totient is φ = 15717240.

The previous prime is 20211949. The next prime is 20211967. The reversal of 20211961 is 16911202.

It is a de Polignac number, because none of the positive numbers 2^k-20211961 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211967) 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 23 ways as a sum of consecutive naturals, for example, 41260 + ... + 41746.

Almost surely, 2^20211961 is an apocalyptic number.

It is an amenable number.

20211961 is a deficient number, since it is larger than the sum of its proper divisors (5749639).

20211961 is an equidigital number, since it uses as much as digits as its factorization.

20211961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530 (or 505 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 22.

The square root of 20211961 is about 4495.7714577145. The cubic root of 20211961 is about 272.3973116994.

The spelling of 20211961 in words is "twenty million, two hundred eleven thousand, nine hundred sixty-one".