3665921 has 8 divisors (see below), whose sum is σ = 4233600. Its totient is φ = 3109248.

The previous prime is 3665911. The next prime is 3665939. The reversal of 3665921 is 1295663.

3665921 = T₂₂₅ + T₂₂₆ + ... + T₃₂₁.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-3665921 is a prime.

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (3665911) 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, 2021 + ... + 3378.

It is an arithmetic number, because the mean of its divisors is an integer number (529200).

It is a Proth number, since it is equal to 895 ⋅ 2¹² + 1 and 895 < 2¹².

Almost surely, 2^3665921 is an apocalyptic number.

It is an amenable number.

3665921 is a deficient number, since it is larger than the sum of its proper divisors (567679).

3665921 is an equidigital number, since it uses as much as digits as its factorization.

3665921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5503.

The product of its digits is 9720, while the sum is 32.

The square root of 3665921 is about 1914.6594997545. The cubic root of 3665921 is about 154.1917132263.

The spelling of 3665921 in words is "three million, six hundred sixty-five thousand, nine hundred twenty-one".