20561967 has 6 divisors (see below), whose sum is σ = 29700632. Its totient is φ = 13707972.

The previous prime is 20561927. The next prime is 20561999. The reversal of 20561967 is 76916502.

20561967 is a `hidden beast` number, since 2 + 0 + 561 + 96 + 7 = 666.

It is not a de Polignac number, because 20561967 - 2⁶ = 20561903 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 (20561917) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1142323 + ... + 1142340.

Almost surely, 2^20561967 is an apocalyptic number.

20561967 is a deficient number, since it is larger than the sum of its proper divisors (9138665).

20561967 is a wasteful number, since it uses less digits than its factorization.

20561967 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2284669 (or 2284666 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 20561967 is about 4534.5305159410. The cubic root of 20561967 is about 273.9606697592.

It can be divided in two parts, 20561 and 967, that added together give a triangular number (21528 = T₂₀₇).

The spelling of 20561967 in words is "twenty million, five hundred sixty-one thousand, nine hundred sixty-seven".