77159991 has 16 divisors (see below), whose sum is σ = 111591648. Its totient is φ = 47232000.

The previous prime is 77159987. The next prime is 77160001. The reversal of 77159991 is 19995177.

It is a happy number.

It is not a de Polignac number, because 77159991 - 2² = 77159987 is a prime.

It is a super-2 number, since 2×77159991² = 11907328422240162, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 77159991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77159941) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16360 + ... + 20541.

It is an arithmetic number, because the mean of its divisors is an integer number (6974478).

Almost surely, 2^77159991 is an apocalyptic number.

77159991 is a deficient number, since it is larger than the sum of its proper divisors (34431657).

77159991 is a wasteful number, since it uses less digits than its factorization.

77159991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36962.

The product of its digits is 178605, while the sum is 48.

The square root of 77159991 is about 8784.0759901085. The cubic root of 77159991 is about 425.7265376680.

The spelling of 77159991 in words is "seventy-seven million, one hundred fifty-nine thousand, nine hundred ninety-one".