77972615641 has 2 divisors, whose sum is σ = 77972615642. Its totient is φ = 77972615640.

The previous prime is 77972615603. The next prime is 77972615647. The reversal of 77972615641 is 14651627977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 73235184400 + 4737431241 = 270620^2 + 68829^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77972615641 is a prime.

It is not a weakly prime, because it can be changed into another prime (77972615647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38986307820 + 38986307821.

It is an arithmetic number, because the mean of its divisors is an integer number (38986307821).

Almost surely, 2^77972615641 is an apocalyptic number.

It is an amenable number.

77972615641 is a deficient number, since it is larger than the sum of its proper divisors (1).

77972615641 is an equidigital number, since it uses as much as digits as its factorization.

77972615641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4445280, while the sum is 55.

The spelling of 77972615641 in words is "seventy-seven billion, nine hundred seventy-two million, six hundred fifteen thousand, six hundred forty-one".