3921640 has 16 divisors (see below), whose sum is σ = 8823780. Its totient is φ = 1568640.

The previous prime is 3921637. The next prime is 3921649. The reversal of 3921640 is 461293.

It can be written as a sum of positive squares in 2 ways, for example, as 3896676 + 24964 = 1974^2 + 158^2 .

It is not an unprimeable number, because it can be changed into a prime (3921649) 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, 48981 + ... + 49060.

Almost surely, 2^3921640 is an apocalyptic number.

It is an amenable number.

3921640 is an abundant number, since it is smaller than the sum of its proper divisors (4902140).

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

3921640 is a wasteful number, since it uses less digits than its factorization.

3921640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98052 (or 98048 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 3921640 is about 1980.3131065566. The cubic root of 3921640 is about 157.6966888455.

The spelling of 3921640 in words is "three million, nine hundred twenty-one thousand, six hundred forty".