77961321 has 12 divisors (see below), whose sum is σ = 112706100. Its totient is φ = 51930240.

The previous prime is 77961307. The next prime is 77961343. The reversal of 77961321 is 12316977.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 29811600 + 48149721 = 5460^2 + 6939^2 .

It is not a de Polignac number, because 77961321 - 2²⁵ = 44406889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (77963321) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10405 + ... + 16253.

It is an arithmetic number, because the mean of its divisors is an integer number (9392175).

Almost surely, 2^77961321 is an apocalyptic number.

It is an amenable number.

77961321 is a deficient number, since it is larger than the sum of its proper divisors (34744779).

77961321 is a wasteful number, since it uses less digits than its factorization.

77961321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7336 (or 7333 counting only the distinct ones).

The product of its digits is 15876, while the sum is 36.

The square root of 77961321 is about 8829.5708276224. The cubic root of 77961321 is about 427.1952316357.

The spelling of 77961321 in words is "seventy-seven million, nine hundred sixty-one thousand, three hundred twenty-one".