77261389 has 2 divisors, whose sum is σ = 77261390. Its totient is φ = 77261388.

The previous prime is 77261369. The next prime is 77261399. The reversal of 77261389 is 98316277.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59028489 + 18232900 = 7683^2 + 4270^2 .

It is a cyclic number.

It is not a de Polignac number, because 77261389 - 2²¹ = 75164237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77261309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38630694 + 38630695.

It is an arithmetic number, because the mean of its divisors is an integer number (38630695).

Almost surely, 2^77261389 is an apocalyptic number.

It is an amenable number.

77261389 is a deficient number, since it is larger than the sum of its proper divisors (1).

77261389 is an equidigital number, since it uses as much as digits as its factorization.

77261389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008, while the sum is 43.

The square root of 77261389 is about 8789.8457893185. The cubic root of 77261389 is about 425.9129422341.

The spelling of 77261389 in words is "seventy-seven million, two hundred sixty-one thousand, three hundred eighty-nine".