3991121600 has 42 divisors (see below), whose sum is σ = 9820657524. Its totient is φ = 1596448000.

The previous prime is 3991121573. The next prime is 3991121609. The reversal of 3991121600 is 61211993.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (3991121609) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1245626 + ... + 1248825.

Almost surely, 2^3991121600 is an apocalyptic number.

It is an amenable number.

3991121600 is an abundant number, since it is smaller than the sum of its proper divisors (5829535924).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3991121600 is a wasteful number, since it uses less digits than its factorization.

3991121600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2494473 (or 2494458 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 32.

The square root of 3991121600 is about 63175.3242967537. The cubic root of 3991121600 is about 1586.2257168225.

The spelling of 3991121600 in words is "three billion, nine hundred ninety-one million, one hundred twenty-one thousand, six hundred".