130728561 has 4 divisors (see below), whose sum is σ = 174304752. Its totient is φ = 87152372.

The previous prime is 130728547. The next prime is 130728583. The reversal of 130728561 is 165827031.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165827031 = 3 ⋅55275677.

It is a cyclic number.

It is not a de Polignac number, because 130728561 - 2⁶ = 130728497 is a prime.

It is a super-2 number, since 2×130728561² = 34179913322261442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (130728061) 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, 21788091 + ... + 21788096.

It is an arithmetic number, because the mean of its divisors is an integer number (43576188).

Almost surely, 2^130728561 is an apocalyptic number.

It is an amenable number.

130728561 is a deficient number, since it is larger than the sum of its proper divisors (43576191).

130728561 is an equidigital number, since it uses as much as digits as its factorization.

130728561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43576190.

The product of its (nonzero) digits is 10080, while the sum is 33.

The square root of 130728561 is about 11433.6591255818. The cubic root of 130728561 is about 507.5242836625.

The spelling of 130728561 in words is "one hundred thirty million, seven hundred twenty-eight thousand, five hundred sixty-one".