3929921 has 4 divisors (see below), whose sum is σ = 3985344. Its totient is φ = 3874500.

The previous prime is 3929917. The next prime is 3929923. The reversal of 3929921 is 1299293.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 3929921 - 2² = 3929917 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 (3929923) 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, 27605 + ... + 27746.

It is an arithmetic number, because the mean of its divisors is an integer number (996336).

Almost surely, 2^3929921 is an apocalyptic number.

It is an amenable number.

3929921 is a deficient number, since it is larger than the sum of its proper divisors (55423).

3929921 is an equidigital number, since it uses as much as digits as its factorization.

3929921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55422.

The product of its digits is 8748, while the sum is 35.

The square root of 3929921 is about 1982.4028349455. The cubic root of 3929921 is about 157.8076091220.

The spelling of 3929921 in words is "three million, nine hundred twenty-nine thousand, nine hundred twenty-one".