77921012171 has 2 divisors, whose sum is σ = 77921012172. Its totient is φ = 77921012170.

The previous prime is 77921012111. The next prime is 77921012177. The reversal of 77921012171 is 17121012977.

It is a strong prime.

It is an emirp because it is prime and its reverse (17121012977) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77921012171 is a prime.

It is not a weakly prime, because it can be changed into another prime (77921012177) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38960506085 + 38960506086.

It is an arithmetic number, because the mean of its divisors is an integer number (38960506086).

Almost surely, 2^77921012171 is an apocalyptic number.

77921012171 is a deficient number, since it is larger than the sum of its proper divisors (1).

77921012171 is an equidigital number, since it uses as much as digits as its factorization.

77921012171 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12348, while the sum is 38.

The spelling of 77921012171 in words is "seventy-seven billion, nine hundred twenty-one million, twelve thousand, one hundred seventy-one".