3921645640 has 64 divisors (see below), whose sum is σ = 9957816000. Its totient is φ = 1376874240.

The previous prime is 3921645631. The next prime is 3921645641. The reversal of 3921645640 is 465461293.

3921645640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 3921645593 and 3921645602.

It is not an unprimeable number, because it can be changed into a prime (3921645641) 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, 140910 + ... + 166429.

It is an arithmetic number, because the mean of its divisors is an integer number (155590875).

Almost surely, 2^3921645640 is an apocalyptic number.

It is an amenable number.

3921645640 is an abundant number, since it is smaller than the sum of its proper divisors (6036170360).

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

3921645640 is a wasteful number, since it uses less digits than its factorization.

3921645640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 307390 (or 307386 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 3921645640 is about 62623.0440013898. The cubic root of 3921645640 is about 1576.9676444385.

The spelling of 3921645640 in words is "three billion, nine hundred twenty-one million, six hundred forty-five thousand, six hundred forty".