77881531 has 12 divisors (see below), whose sum is σ = 97566672. Its totient is φ = 61620048.

The previous prime is 77881487. The next prime is 77881543. The reversal of 77881531 is 13518877.

It is a happy number.

It is not a de Polignac number, because 77881531 - 2¹⁷ = 77750459 is a prime.

It is a super-2 number, since 2×77881531² = 12131065741807922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (77881571) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 60495 + ... + 61768.

It is an arithmetic number, because the mean of its divisors is an integer number (8130556).

Almost surely, 2^77881531 is an apocalyptic number.

77881531 is a deficient number, since it is larger than the sum of its proper divisors (19685141).

77881531 is a wasteful number, since it uses less digits than its factorization.

77881531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122290 (or 122283 counting only the distinct ones).

The product of its digits is 47040, while the sum is 40.

The square root of 77881531 is about 8825.0513312955. The cubic root of 77881531 is about 427.0494433474.

The spelling of 77881531 in words is "seventy-seven million, eight hundred eighty-one thousand, five hundred thirty-one".