77718749 has 2 divisors, whose sum is σ = 77718750. Its totient is φ = 77718748.

The previous prime is 77718733. The next prime is 77718761. The reversal of 77718749 is 94781777.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59013124 + 18705625 = 7682^2 + 4325^2 .

It is a cyclic number.

It is not a de Polignac number, because 77718749 - 2⁴ = 77718733 is a prime.

It is a super-2 number, since 2×77718749² = 12080407892250002, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 77718697 and 77718706.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77718769) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38859374 + 38859375.

It is an arithmetic number, because the mean of its divisors is an integer number (38859375).

Almost surely, 2^77718749 is an apocalyptic number.

It is an amenable number.

77718749 is a deficient number, since it is larger than the sum of its proper divisors (1).

77718749 is an equidigital number, since it uses as much as digits as its factorization.

77718749 is an evil number, because the sum of its binary digits is even.

The product of its digits is 691488, while the sum is 50.

The square root of 77718749 is about 8815.8237845365. The cubic root of 77718749 is about 426.7517071567.

The spelling of 77718749 in words is "seventy-seven million, seven hundred eighteen thousand, seven hundred forty-nine".