1961645872 has 20 divisors (see below), whose sum is σ = 3903411376. Its totient is φ = 954313920.

The previous prime is 1961645867. The next prime is 1961645879. The reversal of 1961645872 is 2785461691.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (1961645879) 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, 1656204 + ... + 1657387.

Almost surely, 2^1961645872 is an apocalyptic number.

It is an amenable number.

1961645872 is a deficient number, since it is larger than the sum of its proper divisors (1941765504).

1961645872 is a wasteful number, since it uses less digits than its factorization.

1961645872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3313636 (or 3313630 counting only the distinct ones).

The product of its digits is 725760, while the sum is 49.

The square root of 1961645872 is about 44290.4715712082. The cubic root of 1961645872 is about 1251.8151489383.

The spelling of 1961645872 in words is "one billion, nine hundred sixty-one million, six hundred forty-five thousand, eight hundred seventy-two".