77981573 has 2 divisors, whose sum is σ = 77981574. Its totient is φ = 77981572.

The previous prime is 77981521. The next prime is 77981581. The reversal of 77981573 is 37518977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69588964 + 8392609 = 8342^2 + 2897^2 .

It is a cyclic number.

It is not a de Polignac number, because 77981573 - 2⁶ = 77981509 is a prime.

It is a super-2 number, since 2×77981573² = 12162251455108658, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77981503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38990786 + 38990787.

It is an arithmetic number, because the mean of its divisors is an integer number (38990787).

Almost surely, 2^77981573 is an apocalyptic number.

It is an amenable number.

77981573 is a deficient number, since it is larger than the sum of its proper divisors (1).

77981573 is an equidigital number, since it uses as much as digits as its factorization.

77981573 is an evil number, because the sum of its binary digits is even.

The product of its digits is 370440, while the sum is 47.

The square root of 77981573 is about 8830.7175812614. The cubic root of 77981573 is about 427.2322192457.

The spelling of 77981573 in words is "seventy-seven million, nine hundred eighty-one thousand, five hundred seventy-three".