77561131 has 2 divisors, whose sum is σ = 77561132. Its totient is φ = 77561130.

The previous prime is 77561119. The next prime is 77561147. The reversal of 77561131 is 13116577.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 77561131 - 2⁹ = 77560619 is a prime.

It is a super-2 number, since 2×77561131² = 12031458083998322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 77561093 and 77561102.

It is not a weakly prime, because it can be changed into another prime (77561831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38780565 + 38780566.

It is an arithmetic number, because the mean of its divisors is an integer number (38780566).

Almost surely, 2^77561131 is an apocalyptic number.

77561131 is a deficient number, since it is larger than the sum of its proper divisors (1).

77561131 is an equidigital number, since it uses as much as digits as its factorization.

77561131 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4410, while the sum is 31.

The square root of 77561131 is about 8806.8797539197. The cubic root of 77561131 is about 426.4630197451.

The spelling of 77561131 in words is "seventy-seven million, five hundred sixty-one thousand, one hundred thirty-one".