77113721 has 2 divisors, whose sum is σ = 77113722. Its totient is φ = 77113720.

The previous prime is 77113711. The next prime is 77113727. The reversal of 77113721 is 12731177.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43705321 + 33408400 = 6611^2 + 5780^2 .

It is a cyclic number.

It is not a de Polignac number, because 77113721 - 2⁶ = 77113657 is a prime.

It is not a weakly prime, because it can be changed into another prime (77113727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38556860 + 38556861.

It is an arithmetic number, because the mean of its divisors is an integer number (38556861).

Almost surely, 2^77113721 is an apocalyptic number.

It is an amenable number.

77113721 is a deficient number, since it is larger than the sum of its proper divisors (1).

77113721 is an equidigital number, since it uses as much as digits as its factorization.

77113721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2058, while the sum is 29.

The square root of 77113721 is about 8781.4418519967. The cubic root of 77113721 is about 425.6414231528.

Adding to 77113721 its reverse (12731177), we get a palindrome (89844898).

The spelling of 77113721 in words is "seventy-seven million, one hundred thirteen thousand, seven hundred twenty-one".