77476751621 has 2 divisors, whose sum is σ = 77476751622. Its totient is φ = 77476751620.

The previous prime is 77476751501. The next prime is 77476751623. The reversal of 77476751621 is 12615767477.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76044129121 + 1432622500 = 275761^2 + 37850^2 .

It is a cyclic number.

It is not a de Polignac number, because 77476751621 - 2³⁰ = 76403009797 is a prime.

It is a super-2 number, since 2×77476751621² (a number of 23 digits) contains 22 as substring.

Together with 77476751623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77476751623) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38738375810 + 38738375811.

It is an arithmetic number, because the mean of its divisors is an integer number (38738375811).

Almost surely, 2^77476751621 is an apocalyptic number.

It is an amenable number.

77476751621 is a deficient number, since it is larger than the sum of its proper divisors (1).

77476751621 is an equidigital number, since it uses as much as digits as its factorization.

77476751621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3457440, while the sum is 53.

The spelling of 77476751621 in words is "seventy-seven billion, four hundred seventy-six million, seven hundred fifty-one thousand, six hundred twenty-one".