76756721 has 2 divisors, whose sum is σ = 76756722. Its totient is φ = 76756720.

The previous prime is 76756711. The next prime is 76756723. The reversal of 76756721 is 12765767.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76755121 + 1600 = 8761^2 + 40^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-76756721 is a prime.

Together with 76756723, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (76756723) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38378360 + 38378361.

It is an arithmetic number, because the mean of its divisors is an integer number (38378361).

Almost surely, 2^76756721 is an apocalyptic number.

It is an amenable number.

76756721 is a deficient number, since it is larger than the sum of its proper divisors (1).

76756721 is an equidigital number, since it uses as much as digits as its factorization.

76756721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 123480, while the sum is 41.

The square root of 76756721 is about 8761.0913133011. The cubic root of 76756721 is about 424.9835675307.

It can be divided in two parts, 76756 and 721, that added together give a palindrome (77477).

The spelling of 76756721 in words is "seventy-six million, seven hundred fifty-six thousand, seven hundred twenty-one".