20961893 has 4 divisors (see below), whose sum is σ = 20976588. Its totient is φ = 20947200.

The previous prime is 20961887. The next prime is 20961907. The reversal of 20961893 is 39816902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20268004 + 693889 = 4502^2 + 833^2 .

It is a cyclic number.

It is not a de Polignac number, because 20961893 - 2²⁰ = 19913317 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20961803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4946 + ... + 8147.

It is an arithmetic number, because the mean of its divisors is an integer number (5244147).

Almost surely, 2^20961893 is an apocalyptic number.

It is an amenable number.

20961893 is a deficient number, since it is larger than the sum of its proper divisors (14695).

20961893 is a wasteful number, since it uses less digits than its factorization.

20961893 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14694.

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

The square root of 20961893 is about 4578.4159924585. The cubic root of 20961893 is about 275.7254367164.

The spelling of 20961893 in words is "twenty million, nine hundred sixty-one thousand, eight hundred ninety-three".