77944621 has 2 divisors, whose sum is σ = 77944622. Its totient is φ = 77944620.

The previous prime is 77944597. The next prime is 77944627. The reversal of 77944621 is 12644977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75429225 + 2515396 = 8685^2 + 1586^2 .

It is a cyclic number.

It is not a de Polignac number, because 77944621 - 2⁵ = 77944589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77944627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38972310 + 38972311.

It is an arithmetic number, because the mean of its divisors is an integer number (38972311).

Almost surely, 2^77944621 is an apocalyptic number.

It is an amenable number.

77944621 is a deficient number, since it is larger than the sum of its proper divisors (1).

77944621 is an equidigital number, since it uses as much as digits as its factorization.

77944621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 40.

The square root of 77944621 is about 8828.6250911453. The cubic root of 77944621 is about 427.1647264667.

The spelling of 77944621 in words is "seventy-seven million, nine hundred forty-four thousand, six hundred twenty-one".