77242639 has 2 divisors, whose sum is σ = 77242640. Its totient is φ = 77242638.

The previous prime is 77242637. The next prime is 77242651. The reversal of 77242639 is 93624277.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 77242639 - 2¹ = 77242637 is a prime.

Together with 77242637, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77242637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38621319 + 38621320.

It is an arithmetic number, because the mean of its divisors is an integer number (38621320).

Almost surely, 2^77242639 is an apocalyptic number.

77242639 is a deficient number, since it is larger than the sum of its proper divisors (1).

77242639 is an equidigital number, since it uses as much as digits as its factorization.

77242639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 127008, while the sum is 40.

The square root of 77242639 is about 8788.7791529882. The cubic root of 77242639 is about 425.8784855502.

The spelling of 77242639 in words is "seventy-seven million, two hundred forty-two thousand, six hundred thirty-nine".