3645907721 has 8 divisors (see below), whose sum is σ = 3818897280. Its totient is φ = 3474124192.

The previous prime is 3645907697. The next prime is 3645907751. The reversal of 3645907721 is 1277095463.

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 3645907721 - 2²² = 3641713417 is a prime.

It is a super-2 number, since 2×3645907721² = 26585286220094827682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3645907751) 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, 295316 + ... + 307413.

It is an arithmetic number, because the mean of its divisors is an integer number (477362160).

Almost surely, 2^3645907721 is an apocalyptic number.

It is an amenable number.

3645907721 is a deficient number, since it is larger than the sum of its proper divisors (172989559).

3645907721 is a wasteful number, since it uses less digits than its factorization.

3645907721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 603015.

The product of its (nonzero) digits is 317520, while the sum is 44.

The square root of 3645907721 is about 60381.3524277156. The cubic root of 3645907721 is about 1539.1060929347.

The spelling of 3645907721 in words is "three billion, six hundred forty-five million, nine hundred seven thousand, seven hundred twenty-one".