130915721 has 4 divisors (see below), whose sum is σ = 131794500. Its totient is φ = 130036944.

The previous prime is 130915717. The next prime is 130915723. The reversal of 130915721 is 127519031.

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 52345225 + 78570496 = 7235^2 + 8864^2 .

It is a cyclic number.

It is not a de Polignac number, because 130915721 - 2² = 130915717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (130915723) 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, 439166 + ... + 439463.

It is an arithmetic number, because the mean of its divisors is an integer number (32948625).

Almost surely, 2^130915721 is an apocalyptic number.

It is an amenable number.

130915721 is a deficient number, since it is larger than the sum of its proper divisors (878779).

130915721 is an equidigital number, since it uses as much as digits as its factorization.

130915721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 878778.

The product of its (nonzero) digits is 1890, while the sum is 29.

The square root of 130915721 is about 11441.8408046957. The cubic root of 130915721 is about 507.7663703947.

The spelling of 130915721 in words is "one hundred thirty million, nine hundred fifteen thousand, seven hundred twenty-one".