77997555 has 12 divisors (see below), whose sum is σ = 135195840. Its totient is φ = 41598672.

The previous prime is 77997551. The next prime is 77997583. The reversal of 77997555 is 55579977.

It is not a de Polignac number, because 77997555 - 2² = 77997551 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77997551) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 866595 + ... + 866684.

It is an arithmetic number, because the mean of its divisors is an integer number (11266320).

Almost surely, 2^77997555 is an apocalyptic number.

77997555 is a deficient number, since it is larger than the sum of its proper divisors (57198285).

77997555 is a wasteful number, since it uses less digits than its factorization.

77997555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1733290 (or 1733287 counting only the distinct ones).

The product of its digits is 3472875, while the sum is 54.

The square root of 77997555 is about 8831.6224443757. The cubic root of 77997555 is about 427.2614037426.

The spelling of 77997555 in words is "seventy-seven million, nine hundred ninety-seven thousand, five hundred fifty-five".