77964788621 has 2 divisors, whose sum is σ = 77964788622. Its totient is φ = 77964788620.

The previous prime is 77964788609. The next prime is 77964788633. The reversal of 77964788621 is 12688746977.

It is a balanced prime because it is at equal distance from previous prime (77964788609) and next prime (77964788633).

It can be written as a sum of positive squares in only one way, i.e., 77947056100 + 17732521 = 279190^2 + 4211^2 .

It is a cyclic number.

It is not a de Polignac number, because 77964788621 - 2²² = 77960594317 is a prime.

It is a super-2 number, since 2×77964788621² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77964785621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38982394310 + 38982394311.

It is an arithmetic number, because the mean of its divisors is an integer number (38982394311).

Almost surely, 2^77964788621 is an apocalyptic number.

It is an amenable number.

77964788621 is a deficient number, since it is larger than the sum of its proper divisors (1).

77964788621 is an equidigital number, since it uses as much as digits as its factorization.

77964788621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 56899584, while the sum is 65.

The spelling of 77964788621 in words is "seventy-seven billion, nine hundred sixty-four million, seven hundred eighty-eight thousand, six hundred twenty-one".