77139431 has 4 divisors (see below), whose sum is σ = 77271432. Its totient is φ = 77007432.

The previous prime is 77139397. The next prime is 77139451. The reversal of 77139431 is 13493177.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77139431 is a prime.

It is a super-2 number, since 2×77139431² = 11900983630007522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 77139391 and 77139400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77139451) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65120 + ... + 66293.

It is an arithmetic number, because the mean of its divisors is an integer number (19317858).

Almost surely, 2^77139431 is an apocalyptic number.

77139431 is a deficient number, since it is larger than the sum of its proper divisors (132001).

77139431 is a wasteful number, since it uses less digits than its factorization.

77139431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132000.

The product of its digits is 15876, while the sum is 35.

The square root of 77139431 is about 8782.9056126091. The cubic root of 77139431 is about 425.6887213720.

The spelling of 77139431 in words is "seventy-seven million, one hundred thirty-nine thousand, four hundred thirty-one".