31184561 has 2 divisors, whose sum is σ = 31184562. Its totient is φ = 31184560.

The previous prime is 31184557. The next prime is 31184563. The reversal of 31184561 is 16548113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28143025 + 3041536 = 5305^2 + 1744^2 .

It is a cyclic number.

It is not a de Polignac number, because 31184561 - 2² = 31184557 is a prime.

Together with 31184563, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (31184563) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15592280 + 15592281.

It is an arithmetic number, because the mean of its divisors is an integer number (15592281).

Almost surely, 2^31184561 is an apocalyptic number.

It is an amenable number.

31184561 is a deficient number, since it is larger than the sum of its proper divisors (1).

31184561 is an equidigital number, since it uses as much as digits as its factorization.

31184561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2880, while the sum is 29.

The square root of 31184561 is about 5584.3138343041. The cubic root of 31184561 is about 314.7602475654.

The spelling of 31184561 in words is "thirty-one million, one hundred eighty-four thousand, five hundred sixty-one".