73991355813 has 18 divisors (see below), whose sum is σ = 106997970534. Its totient is φ = 49271499984.

The previous prime is 73991355803. The next prime is 73991355821. The reversal of 73991355813 is 31855319937.

73991355813 is a `hidden beast` number, since 73 + 9 + 9 + 1 + 3 + 558 + 13 = 666.

It can be written as a sum of positive squares in only one way, i.e., 73775794689 + 215561124 = 271617^2 + 14682^2 .

It is not a de Polignac number, because 73991355813 - 2¹² = 73991351717 is a prime.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 73991355813.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73991355803) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 30236356 + ... + 30238802.

Almost surely, 2^73991355813 is an apocalyptic number.

It is an amenable number.

73991355813 is a deficient number, since it is larger than the sum of its proper divisors (33006614721).

73991355813 is an equidigital number, since it uses as much as digits as its factorization.

73991355813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6273 (or 3823 counting only the distinct ones).

The product of its digits is 3061800, while the sum is 54.

The spelling of 73991355813 in words is "seventy-three billion, nine hundred ninety-one million, three hundred fifty-five thousand, eight hundred thirteen".