77136981 has 4 divisors (see below), whose sum is σ = 102849312. Its totient is φ = 51424652.

The previous prime is 77136967. The next prime is 77136989. The reversal of 77136981 is 18963177.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 77136981 - 2¹³ = 77128789 is a prime.

It is a super-2 number, since 2×77136981² = 11900227675588722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77136989) 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, 12856161 + ... + 12856166.

It is an arithmetic number, because the mean of its divisors is an integer number (25712328).

Almost surely, 2^77136981 is an apocalyptic number.

It is an amenable number.

77136981 is a deficient number, since it is larger than the sum of its proper divisors (25712331).

77136981 is a wasteful number, since it uses less digits than its factorization.

77136981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25712330.

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

The square root of 77136981 is about 8782.7661360189. The cubic root of 77136981 is about 425.6842146047.

The spelling of 77136981 in words is "seventy-seven million, one hundred thirty-six thousand, nine hundred eighty-one".