61287931 has 2 divisors, whose sum is σ = 61287932. Its totient is φ = 61287930.

The previous prime is 61287929. The next prime is 61287937. The reversal of 61287931 is 13978216.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61287931 - 2¹ = 61287929 is a prime.

It is a super-2 number, since 2×61287931² = 7512420972521522, which contains 22 as substring.

Together with 61287929, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (61287937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30643965 + 30643966.

It is an arithmetic number, because the mean of its divisors is an integer number (30643966).

Almost surely, 2^61287931 is an apocalyptic number.

61287931 is a deficient number, since it is larger than the sum of its proper divisors (1).

61287931 is an equidigital number, since it uses as much as digits as its factorization.

61287931 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18144, while the sum is 37.

The square root of 61287931 is about 7828.6608688843. The cubic root of 61287931 is about 394.2681122369.

The spelling of 61287931 in words is "sixty-one million, two hundred eighty-seven thousand, nine hundred thirty-one".