77218157 has 2 divisors, whose sum is σ = 77218158. Its totient is φ = 77218156.

The previous prime is 77218139. The next prime is 77218181. The reversal of 77218157 is 75181277.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75446596 + 1771561 = 8686^2 + 1331^2 .

It is a cyclic number.

It is not a de Polignac number, because 77218157 - 2⁶ = 77218093 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 77218157.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77218957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38609078 + 38609079.

It is an arithmetic number, because the mean of its divisors is an integer number (38609079).

Almost surely, 2^77218157 is an apocalyptic number.

It is an amenable number.

77218157 is a deficient number, since it is larger than the sum of its proper divisors (1).

77218157 is an equidigital number, since it uses as much as digits as its factorization.

77218157 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27440, while the sum is 38.

The square root of 77218157 is about 8787.3862439294. The cubic root of 77218157 is about 425.8334868338.

The spelling of 77218157 in words is "seventy-seven million, two hundred eighteen thousand, one hundred fifty-seven".