77616981 has 32 divisors (see below), whose sum is σ = 124467840. Its totient is φ = 47520000.

The previous prime is 77616971. The next prime is 77616997. The reversal of 77616981 is 18961677.

It is not a de Polignac number, because 77616981 - 2⁷ = 77616853 is a prime.

It is a super-2 number, since 2×77616981² = 12048791479108722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77616911) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 87661 + ... + 88541.

It is an arithmetic number, because the mean of its divisors is an integer number (3889620).

Almost surely, 2^77616981 is an apocalyptic number.

It is an amenable number.

77616981 is a deficient number, since it is larger than the sum of its proper divisors (46850859).

77616981 is a wasteful number, since it uses less digits than its factorization.

77616981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1154 (or 1148 counting only the distinct ones).

The product of its digits is 127008, while the sum is 45.

The square root of 77616981 is about 8810.0499998581. The cubic root of 77616981 is about 426.5653572807.

The spelling of 77616981 in words is "seventy-seven million, six hundred sixteen thousand, nine hundred eighty-one".