76643888521 has 2 divisors, whose sum is σ = 76643888522. Its totient is φ = 76643888520.

The previous prime is 76643888491. The next prime is 76643888537. The reversal of 76643888521 is 12588834667.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 56899423296 + 19744465225 = 238536^2 + 140515^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-76643888521 is a prime.

It is not a weakly prime, because it can be changed into another prime (76643888921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38321944260 + 38321944261.

It is an arithmetic number, because the mean of its divisors is an integer number (38321944261).

Almost surely, 2^76643888521 is an apocalyptic number.

It is an amenable number.

76643888521 is a deficient number, since it is larger than the sum of its proper divisors (1).

76643888521 is an equidigital number, since it uses as much as digits as its factorization.

76643888521 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15482880, while the sum is 58.

The spelling of 76643888521 in words is "seventy-six billion, six hundred forty-three million, eight hundred eighty-eight thousand, five hundred twenty-one".