77997551 has 2 divisors, whose sum is σ = 77997552. Its totient is φ = 77997550.

The previous prime is 77997541. The next prime is 77997583. The reversal of 77997551 is 15579977.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77997551 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77997551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77997541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38998775 + 38998776.

It is an arithmetic number, because the mean of its divisors is an integer number (38998776).

Almost surely, 2^77997551 is an apocalyptic number.

77997551 is a deficient number, since it is larger than the sum of its proper divisors (1).

77997551 is an equidigital number, since it uses as much as digits as its factorization.

77997551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 694575, while the sum is 50.

The square root of 77997551 is about 8831.6222179167. The cubic root of 77997551 is about 427.2613964388.

The spelling of 77997551 in words is "seventy-seven million, nine hundred ninety-seven thousand, five hundred fifty-one".