7997129813 has 4 divisors (see below), whose sum is σ = 8272892940. Its totient is φ = 7721366688.

The previous prime is 7997129797. The next prime is 7997129821. The reversal of 7997129813 is 3189217997.

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 5219629009 + 2777500804 = 72247^2 + 52702^2 .

It is a cyclic number.

It is not a de Polignac number, because 7997129813 - 2⁴ = 7997129797 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7997129843) 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, 137881520 + ... + 137881577.

It is an arithmetic number, because the mean of its divisors is an integer number (2068223235).

Almost surely, 2^7997129813 is an apocalyptic number.

It is an amenable number.

7997129813 is a deficient number, since it is larger than the sum of its proper divisors (275763127).

7997129813 is a wasteful number, since it uses less digits than its factorization.

7997129813 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275763126.

The product of its digits is 1714608, while the sum is 56.

The square root of 7997129813 is about 89426.6728275183. The cubic root of 7997129813 is about 1999.7607891402.

The spelling of 7997129813 in words is "seven billion, nine hundred ninety-seven million, one hundred twenty-nine thousand, eight hundred thirteen".