77222721 has 16 divisors (see below), whose sum is σ = 111682368. Its totient is φ = 47270400.

The previous prime is 77222713. The next prime is 77222723. The reversal of 77222721 is 12722277.

It is not a de Polignac number, because 77222721 - 2³ = 77222713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77222723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16375 + ... + 20556.

It is an arithmetic number, because the mean of its divisors is an integer number (6980148).

Almost surely, 2^77222721 is an apocalyptic number.

It is an amenable number.

77222721 is a deficient number, since it is larger than the sum of its proper divisors (34459647).

77222721 is a wasteful number, since it uses less digits than its factorization.

77222721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36992.

The product of its digits is 5488, while the sum is 30.

The square root of 77222721 is about 8787.6459305095. The cubic root of 77222721 is about 425.8418763363.

Adding to 77222721 its reverse (12722277), we get a palindrome (89944998).

The spelling of 77222721 in words is "seventy-seven million, two hundred twenty-two thousand, seven hundred twenty-one".