77878941121 has 2 divisors, whose sum is σ = 77878941122. Its totient is φ = 77878941120.

The previous prime is 77878941079. The next prime is 77878941163. The reversal of 77878941121 is 12114987877.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (77878941079) and next prime (77878941163).

It can be written as a sum of positive squares in only one way, i.e., 71468536896 + 6410404225 = 267336^2 + 80065^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77878941121 is a prime.

It is not a weakly prime, because it can be changed into another prime (77878942121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38939470560 + 38939470561.

It is an arithmetic number, because the mean of its divisors is an integer number (38939470561).

Almost surely, 2^77878941121 is an apocalyptic number.

It is an amenable number.

77878941121 is a deficient number, since it is larger than the sum of its proper divisors (1).

77878941121 is an equidigital number, since it uses as much as digits as its factorization.

77878941121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1580544, while the sum is 55.

The spelling of 77878941121 in words is "seventy-seven billion, eight hundred seventy-eight million, nine hundred forty-one thousand, one hundred twenty-one".