77139681 has 8 divisors (see below), whose sum is σ = 106399680. Its totient is φ = 49653072.

The previous prime is 77139679. The next prime is 77139683. The reversal of 77139681 is 18693177.

It is an interprime number because it is at equal distance from previous prime (77139679) and next prime (77139683).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 77139681 - 2¹ = 77139679 is a prime.

It is a super-2 number, since 2×77139681² = 11901060769563522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (77139683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 443245 + ... + 443418.

It is an arithmetic number, because the mean of its divisors is an integer number (13299960).

Almost surely, 2^77139681 is an apocalyptic number.

It is an amenable number.

77139681 is a deficient number, since it is larger than the sum of its proper divisors (29259999).

77139681 is a wasteful number, since it uses less digits than its factorization.

77139681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 886695.

The product of its digits is 63504, while the sum is 42.

The square root of 77139681 is about 8782.9198447897. The cubic root of 77139681 is about 425.6891812409.

The spelling of 77139681 in words is "seventy-seven million, one hundred thirty-nine thousand, six hundred eighty-one".