77021939 has 2 divisors, whose sum is σ = 77021940. Its totient is φ = 77021938.

The previous prime is 77021921. The next prime is 77021947. The reversal of 77021939 is 93912077.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77021939 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77021969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38510969 + 38510970.

It is an arithmetic number, because the mean of its divisors is an integer number (38510970).

Almost surely, 2^77021939 is an apocalyptic number.

77021939 is a deficient number, since it is larger than the sum of its proper divisors (1).

77021939 is an equidigital number, since it uses as much as digits as its factorization.

77021939 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23814, while the sum is 38.

The square root of 77021939 is about 8776.2143889037. The cubic root of 77021939 is about 425.4724876727.

The spelling of 77021939 in words is "seventy-seven million, twenty-one thousand, nine hundred thirty-nine".