76556721 has 8 divisors (see below), whose sum is σ = 102343680. Its totient is φ = 50903792.

The previous prime is 76556653. The next prime is 76556791. The reversal of 76556721 is 12765567.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 76556721 - 2⁹ = 76556209 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 76556721.

It is not an unprimeable number, because it can be changed into a prime (76556791) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32166 + ... + 34463.

It is an arithmetic number, because the mean of its divisors is an integer number (12792960).

Almost surely, 2^76556721 is an apocalyptic number.

It is an amenable number.

76556721 is a deficient number, since it is larger than the sum of its proper divisors (25786959).

76556721 is a wasteful number, since it uses less digits than its factorization.

76556721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67015.

The product of its digits is 88200, while the sum is 39.

The square root of 76556721 is about 8749.6697651969. The cubic root of 76556721 is about 424.6141291158.

It can be divided in two parts, 76556 and 721, that added together give a palindrome (77277).

The spelling of 76556721 in words is "seventy-six million, five hundred fifty-six thousand, seven hundred twenty-one".