3561615721 has 8 divisors (see below), whose sum is σ = 3757428000. Its totient is φ = 3366639360.

The previous prime is 3561615713. The next prime is 3561615731. The reversal of 3561615721 is 1275161653.

3561615721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 3561615721 - 2³ = 3561615713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3561615731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 200215 + ... + 217276.

It is an arithmetic number, because the mean of its divisors is an integer number (469678500).

Almost surely, 2^3561615721 is an apocalyptic number.

It is an amenable number.

3561615721 is a deficient number, since it is larger than the sum of its proper divisors (195812279).

3561615721 is a wasteful number, since it uses less digits than its factorization.

3561615721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417959.

The product of its digits is 37800, while the sum is 37.

The square root of 3561615721 is about 59679.2737975254. The cubic root of 3561615721 is about 1527.1523092558.

The spelling of 3561615721 in words is "three billion, five hundred sixty-one million, six hundred fifteen thousand, seven hundred twenty-one".