128531613 has 16 divisors (see below), whose sum is σ = 204374016. Its totient is φ = 70253040.

The previous prime is 128531609. The next prime is 128531621. The reversal of 128531613 is 316135821.

It is not a de Polignac number, because 128531613 - 2² = 128531609 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128531213) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 132573 + ... + 133538.

It is an arithmetic number, because the mean of its divisors is an integer number (12773376).

Almost surely, 2^128531613 is an apocalyptic number.

It is an amenable number.

128531613 is a deficient number, since it is larger than the sum of its proper divisors (75842403).

128531613 is a wasteful number, since it uses less digits than its factorization.

128531613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266144.

The product of its digits is 4320, while the sum is 30.

The square root of 128531613 is about 11337.1783526590. The cubic root of 128531613 is about 504.6651546235.

The spelling of 128531613 in words is "one hundred twenty-eight million, five hundred thirty-one thousand, six hundred thirteen".