77161621 has 2 divisors, whose sum is σ = 77161622. Its totient is φ = 77161620.

The previous prime is 77161597. The next prime is 77161627. The reversal of 77161621 is 12616177.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64480900 + 12680721 = 8030^2 + 3561^2 .

It is a cyclic number.

It is not a de Polignac number, because 77161621 - 2⁷ = 77161493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77161627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38580810 + 38580811.

It is an arithmetic number, because the mean of its divisors is an integer number (38580811).

Almost surely, 2^77161621 is an apocalyptic number.

It is an amenable number.

77161621 is a deficient number, since it is larger than the sum of its proper divisors (1).

77161621 is an equidigital number, since it uses as much as digits as its factorization.

77161621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3528, while the sum is 31.

The square root of 77161621 is about 8784.1687711473. The cubic root of 77161621 is about 425.7295354624.

Adding to 77161621 its reverse (12616177), we get a palindrome (89777798).

The spelling of 77161621 in words is "seventy-seven million, one hundred sixty-one thousand, six hundred twenty-one".