3815921 has 8 divisors (see below), whose sum is σ = 3950784. Its totient is φ = 3682800.

The previous prime is 3815909. The next prime is 3815923. The reversal of 3815921 is 1295183.

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 3815921 - 2¹⁸ = 3553777 is a prime.

It is a super-2 number, since 2×3815921² = 29122506156482, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3815923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5246 + ... + 5928.

It is an arithmetic number, because the mean of its divisors is an integer number (493848).

Almost surely, 2^3815921 is an apocalyptic number.

It is an amenable number.

3815921 is a deficient number, since it is larger than the sum of its proper divisors (134863).

3815921 is a wasteful number, since it uses less digits than its factorization.

3815921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 871.

The product of its digits is 2160, while the sum is 29.

The square root of 3815921 is about 1953.4382508797. The cubic root of 3815921 is about 156.2667062670.

The spelling of 3815921 in words is "three million, eight hundred fifteen thousand, nine hundred twenty-one".