77959500721 has 8 divisors (see below), whose sum is σ = 80891945960. Its totient is φ = 75070499328.

The previous prime is 77959500713. The next prime is 77959500743. The reversal of 77959500721 is 12700595977.

It can be written as a sum of positive squares in 4 ways, for example, as 37100538225 + 40858962496 = 192615^2 + 202136^2 .

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 77959500721 - 2³ = 77959500713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77959500121) 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, 10857306 + ... + 10864483.

It is an arithmetic number, because the mean of its divisors is an integer number (10111493245).

Almost surely, 2^77959500721 is an apocalyptic number.

It is an amenable number.

77959500721 is a deficient number, since it is larger than the sum of its proper divisors (2932445239).

77959500721 is a wasteful number, since it uses less digits than its factorization.

77959500721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21721923.

The product of its (nonzero) digits is 1389150, while the sum is 52.

The spelling of 77959500721 in words is "seventy-seven billion, nine hundred fifty-nine million, five hundred thousand, seven hundred twenty-one".