77319813121 has 4 divisors (see below), whose sum is σ = 77321672532. Its totient is φ = 77317953712.

The previous prime is 77319813107. The next prime is 77319813133. The reversal of 77319813121 is 12131891377.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 72597374721 + 4722438400 = 269439^2 + 68720^2 .

It is a cyclic number.

It is not a de Polignac number, because 77319813121 - 2⁷ = 77319812993 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (77319813101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 865870 + ... + 950983.

It is an arithmetic number, because the mean of its divisors is an integer number (19330418133).

Almost surely, 2^77319813121 is an apocalyptic number.

It is an amenable number.

77319813121 is a deficient number, since it is larger than the sum of its proper divisors (1859411).

77319813121 is a wasteful number, since it uses less digits than its factorization.

77319813121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1859410.

The product of its digits is 63504, while the sum is 43.

The spelling of 77319813121 in words is "seventy-seven billion, three hundred nineteen million, eight hundred thirteen thousand, one hundred twenty-one".