77621531 has 12 divisors (see below), whose sum is σ = 85248720. Its totient is φ = 70630560.

The previous prime is 77621519. The next prime is 77621543. The reversal of 77621531 is 13512677.

It is an interprime number because it is at equal distance from previous prime (77621519) and next prime (77621543).

It is not a de Polignac number, because 77621531 - 2¹⁴ = 77605147 is a prime.

It is a super-2 number, since 2×77621531² = 12050204149567922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77621501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8765 + ... + 15233.

It is an arithmetic number, because the mean of its divisors is an integer number (7104060).

Almost surely, 2^77621531 is an apocalyptic number.

77621531 is a gapful number since it is divisible by the number (71) formed by its first and last digit.

77621531 is a deficient number, since it is larger than the sum of its proper divisors (7627189).

77621531 is a wasteful number, since it uses less digits than its factorization.

77621531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6566 (or 6553 counting only the distinct ones).

The product of its digits is 8820, while the sum is 32.

The square root of 77621531 is about 8810.3082238932. The cubic root of 77621531 is about 426.5736923745.

The spelling of 77621531 in words is "seventy-seven million, six hundred twenty-one thousand, five hundred thirty-one".