77264221 has 2 divisors, whose sum is σ = 77264222. Its totient is φ = 77264220.

The previous prime is 77264219. The next prime is 77264233. The reversal of 77264221 is 12246277.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77264100 + 121 = 8790^2 + 11^2 .

It is a cyclic number.

It is not a de Polignac number, because 77264221 - 2¹ = 77264219 is a prime.

Together with 77264219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77264281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38632110 + 38632111.

It is an arithmetic number, because the mean of its divisors is an integer number (38632111).

Almost surely, 2^77264221 is an apocalyptic number.

It is an amenable number.

77264221 is a deficient number, since it is larger than the sum of its proper divisors (1).

77264221 is an equidigital number, since it uses as much as digits as its factorization.

77264221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 9408, while the sum is 31.

The square root of 77264221 is about 8790.0068828187. The cubic root of 77264221 is about 425.9181460870.

The spelling of 77264221 in words is "seventy-seven million, two hundred sixty-four thousand, two hundred twenty-one".