3721891 has 16 divisors (see below), whose sum is σ = 4147200. Its totient is φ = 3326400.

The previous prime is 3721877. The next prime is 3721901. The reversal of 3721891 is 1981273.

3721891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 3721891 - 2⁵ = 3721859 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3721811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41775 + ... + 41863.

It is an arithmetic number, because the mean of its divisors is an integer number (259200).

Almost surely, 2^3721891 is an apocalyptic number.

3721891 is a gapful number since it is divisible by the number (31) formed by its first and last digit.

3721891 is a deficient number, since it is larger than the sum of its proper divisors (425309).

3721891 is a wasteful number, since it uses less digits than its factorization.

3721891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210.

The product of its digits is 3024, while the sum is 31.

The square root of 3721891 is about 1929.2203088295. The cubic root of 3721891 is about 154.9724682283.

The spelling of 3721891 in words is "three million, seven hundred twenty-one thousand, eight hundred ninety-one".