77377981 has 2 divisors, whose sum is σ = 77377982. Its totient is φ = 77377980.

The previous prime is 77377973. The next prime is 77377997. The reversal of 77377981 is 18977377.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42968025 + 34409956 = 6555^2 + 5866^2 .

It is a cyclic number.

It is not a de Polignac number, because 77377981 - 2³ = 77377973 is a prime.

It is a super-2 number, since 2×77377981² = 11974703887272722, 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 (77377961) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38688990 + 38688991.

It is an arithmetic number, because the mean of its divisors is an integer number (38688991).

Almost surely, 2^77377981 is an apocalyptic number.

It is an amenable number.

77377981 is a deficient number, since it is larger than the sum of its proper divisors (1).

77377981 is an equidigital number, since it uses as much as digits as its factorization.

77377981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 518616, while the sum is 49.

The square root of 77377981 is about 8796.4754873756. The cubic root of 77377981 is about 426.1270771526.

The spelling of 77377981 in words is "seventy-seven million, three hundred seventy-seven thousand, nine hundred eighty-one".