77693813 has 8 divisors (see below), whose sum is σ = 81891000. Its totient is φ = 73597888.

The previous prime is 77693797. The next prime is 77693857. The reversal of 77693813 is 31839677.

It can be written as a sum of positive squares in 4 ways, for example, as 29571844 + 48121969 = 5438^2 + 6937^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 77693813 - 2⁴ = 77693797 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77693113) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23738 + ... + 26811.

It is an arithmetic number, because the mean of its divisors is an integer number (10236375).

Almost surely, 2^77693813 is an apocalyptic number.

77693813 is the 4712-nd centered heptagonal number.

It is an amenable number.

77693813 is a deficient number, since it is larger than the sum of its proper divisors (4197187).

77693813 is a wasteful number, since it uses less digits than its factorization.

77693813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50631.

The product of its digits is 190512, while the sum is 44.

The square root of 77693813 is about 8814.4093959834. The cubic root of 77693813 is about 426.7060612904.

The spelling of 77693813 in words is "seventy-seven million, six hundred ninety-three thousand, eight hundred thirteen".