1981570609 has 8 divisors (see below), whose sum is σ = 2170483560. Its totient is φ = 1800696576.

The previous prime is 1981570601. The next prime is 1981570639. The reversal of 1981570609 is 9060751891.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 983010609 + 998560000 = 31353^2 + 31600^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1981570609 - 2³ = 1981570601 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1981570601) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2009214 + ... + 2010199.

It is an arithmetic number, because the mean of its divisors is an integer number (271310445).

Almost surely, 2^1981570609 is an apocalyptic number.

It is an amenable number.

1981570609 is a deficient number, since it is larger than the sum of its proper divisors (188912951).

1981570609 is a wasteful number, since it uses less digits than its factorization.

1981570609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4019459.

The product of its (nonzero) digits is 136080, while the sum is 46.

The square root of 1981570609 is about 44514.8358303162. The cubic root of 1981570609 is about 1256.0391723164.

The spelling of 1981570609 in words is "one billion, nine hundred eighty-one million, five hundred seventy thousand, six hundred nine".