61566431 has 4 divisors (see below), whose sum is σ = 61704000. Its totient is φ = 61428864.

The previous prime is 61566413. The next prime is 61566433. The reversal of 61566431 is 13466516.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-61566431 is a prime.

It is a super-2 number, since 2×61566431² = 7580850852155522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61566433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68111 + ... + 69008.

It is an arithmetic number, because the mean of its divisors is an integer number (15426000).

Almost surely, 2^61566431 is an apocalyptic number.

61566431 is a deficient number, since it is larger than the sum of its proper divisors (137569).

61566431 is a wasteful number, since it uses less digits than its factorization.

61566431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137568.

The product of its digits is 12960, while the sum is 32.

The square root of 61566431 is about 7846.4279133884. The cubic root of 61566431 is about 394.8644110816.

The spelling of 61566431 in words is "sixty-one million, five hundred sixty-six thousand, four hundred thirty-one".