77137991 has 8 divisors (see below), whose sum is σ = 89148960. Its totient is φ = 65374848.

The previous prime is 77137979. The next prime is 77138003. The reversal of 77137991 is 19973177.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (77137979) and next prime (77138003).

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

It is not a de Polignac number, because 77137991 - 2¹⁰ = 77136967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77137901) 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, 61286 + ... + 62531.

It is an arithmetic number, because the mean of its divisors is an integer number (11143620).

Almost surely, 2^77137991 is an apocalyptic number.

77137991 is a deficient number, since it is larger than the sum of its proper divisors (12010969).

77137991 is a wasteful number, since it uses less digits than its factorization.

77137991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 123913.

The product of its digits is 83349, while the sum is 44.

The square root of 77137991 is about 8782.8236347999. The cubic root of 77137991 is about 425.6860725081.

The spelling of 77137991 in words is "seventy-seven million, one hundred thirty-seven thousand, nine hundred ninety-one".