3891021 has 8 divisors (see below), whose sum is σ = 5198304. Its totient is φ = 2588880.

The previous prime is 3890981. The next prime is 3891037. The reversal of 3891021 is 1201983.

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

It is not a de Polignac number, because 3891021 - 2¹⁷ = 3759949 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 3890982 and 3891000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3891061) 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, 1135 + ... + 3011.

It is an arithmetic number, because the mean of its divisors is an integer number (649788).

Almost surely, 2^3891021 is an apocalyptic number.

It is an amenable number.

3891021 is a deficient number, since it is larger than the sum of its proper divisors (1307283).

3891021 is a wasteful number, since it uses less digits than its factorization.

3891021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2571.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 3891021 is about 1972.5671091246. The cubic root of 3891021 is about 157.2851997536.

The spelling of 3891021 in words is "three million, eight hundred ninety-one thousand, twenty-one".