3980815621 has 4 divisors (see below), whose sum is σ = 3990743244. Its totient is φ = 3970888000.

The previous prime is 3980815613. The next prime is 3980815649. The reversal of 3980815621 is 1265180893.

3980815621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3873693121 + 107122500 = 62239^2 + 10350^2 .

It is a cyclic number.

It is not a de Polignac number, because 3980815621 - 2³ = 3980815613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3980815021) 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, 4963210 + ... + 4964011.

It is an arithmetic number, because the mean of its divisors is an integer number (997685811).

Almost surely, 2^3980815621 is an apocalyptic number.

It is an amenable number.

3980815621 is a deficient number, since it is larger than the sum of its proper divisors (9927623).

3980815621 is an equidigital number, since it uses as much as digits as its factorization.

3980815621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9927622.

The product of its (nonzero) digits is 103680, while the sum is 43.

The square root of 3980815621 is about 63093.7050822029. The cubic root of 3980815621 is about 1584.8592087025.

The spelling of 3980815621 in words is "three billion, nine hundred eighty million, eight hundred fifteen thousand, six hundred twenty-one".