77288721 has 16 divisors (see below), whose sum is σ = 105006144. Its totient is φ = 50554944.

The previous prime is 77288719. The next prime is 77288767. The reversal of 77288721 is 12788277.

It is not a de Polignac number, because 77288721 - 2¹ = 77288719 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77288711) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 63111 + ... + 64323.

It is an arithmetic number, because the mean of its divisors is an integer number (6562884).

Almost surely, 2^77288721 is an apocalyptic number.

It is an amenable number.

77288721 is a deficient number, since it is larger than the sum of its proper divisors (27717423).

77288721 is a wasteful number, since it uses less digits than its factorization.

77288721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1600.

The product of its digits is 87808, while the sum is 42.

The square root of 77288721 is about 8791.4004003913. The cubic root of 77288721 is about 425.9631599873.

The spelling of 77288721 in words is "seventy-seven million, two hundred eighty-eight thousand, seven hundred twenty-one".