77942989 has 2 divisors, whose sum is σ = 77942990. Its totient is φ = 77942988.

The previous prime is 77942983. The next prime is 77943001. The reversal of 77942989 is 98924977.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42445225 + 35497764 = 6515^2 + 5958^2 .

It is a cyclic number.

It is not a de Polignac number, because 77942989 - 2⁷ = 77942861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77942983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38971494 + 38971495.

It is an arithmetic number, because the mean of its divisors is an integer number (38971495).

Almost surely, 2^77942989 is an apocalyptic number.

It is an amenable number.

77942989 is a deficient number, since it is larger than the sum of its proper divisors (1).

77942989 is an equidigital number, since it uses as much as digits as its factorization.

77942989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2286144, while the sum is 55.

The square root of 77942989 is about 8828.5326640388. The cubic root of 77942989 is about 427.1617451291.

The spelling of 77942989 in words is "seventy-seven million, nine hundred forty-two thousand, nine hundred eighty-nine".