77899949 has 2 divisors, whose sum is σ = 77899950. Its totient is φ = 77899948.

The previous prime is 77899937. The next prime is 77899951. The reversal of 77899949 is 94999877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76650025 + 1249924 = 8755^2 + 1118^2 .

It is a cyclic number.

It is not a de Polignac number, because 77899949 - 2⁸ = 77899693 is a prime.

It is a Sophie Germain prime.

Together with 77899951, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 77899891 and 77899900.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77899999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38949974 + 38949975.

It is an arithmetic number, because the mean of its divisors is an integer number (38949975).

Almost surely, 2^77899949 is an apocalyptic number.

It is an amenable number.

77899949 is a deficient number, since it is larger than the sum of its proper divisors (1).

77899949 is an equidigital number, since it uses as much as digits as its factorization.

77899949 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10287648, while the sum is 62.

The square root of 77899949 is about 8826.0947762870. The cubic root of 77899949 is about 427.0831046302.

The spelling of 77899949 in words is "seventy-seven million, eight hundred ninety-nine thousand, nine hundred forty-nine".