77285981 has 2 divisors, whose sum is σ = 77285982. Its totient is φ = 77285980.

The previous prime is 77285941. The next prime is 77285987. The reversal of 77285981 is 18958277.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 64080025 + 13205956 = 8005^2 + 3634^2 .

It is a cyclic number.

It is not a de Polignac number, because 77285981 - 2²⁶ = 10177117 is a prime.

It is a super-2 number, since 2×77285981² = 11946245718264722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77285987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38642990 + 38642991.

It is an arithmetic number, because the mean of its divisors is an integer number (38642991).

Almost surely, 2^77285981 is an apocalyptic number.

It is an amenable number.

77285981 is a deficient number, since it is larger than the sum of its proper divisors (1).

77285981 is an equidigital number, since it uses as much as digits as its factorization.

77285981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 282240, while the sum is 47.

The square root of 77285981 is about 8791.2445649066. The cubic root of 77285981 is about 425.9581262522.

The spelling of 77285981 in words is "seventy-seven million, two hundred eighty-five thousand, nine hundred eighty-one".