77681407 has 2 divisors, whose sum is σ = 77681408. Its totient is φ = 77681406.

The previous prime is 77681371. The next prime is 77681431. The reversal of 77681407 is 70418677.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77681407 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77681407.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77681437) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38840703 + 38840704.

It is an arithmetic number, because the mean of its divisors is an integer number (38840704).

Almost surely, 2^77681407 is an apocalyptic number.

77681407 is a deficient number, since it is larger than the sum of its proper divisors (1).

77681407 is an equidigital number, since it uses as much as digits as its factorization.

77681407 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 65856, while the sum is 40.

The square root of 77681407 is about 8813.7056338410. The cubic root of 77681407 is about 426.6833482112.

The spelling of 77681407 in words is "seventy-seven million, six hundred eighty-one thousand, four hundred seven".