3971820 has 48 divisors (see below), whose sum is σ = 11340000. Its totient is φ = 1038336.

The previous prime is 3971809. The next prime is 3971833. The reversal of 3971820 is 281793.

It is a happy number.

It is a super-2 number, since 2×3971820² = 31550708224800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2556 + ... + 3804.

It is an arithmetic number, because the mean of its divisors is an integer number (236250).

Almost surely, 2^3971820 is an apocalyptic number.

3971820 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3971820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (5670000).

3971820 is an abundant number, since it is smaller than the sum of its proper divisors (7368180).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3971820 is a wasteful number, since it uses less digits than its factorization.

3971820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1314 (or 1312 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 30.

The square root of 3971820 is about 1992.9425480931. The cubic root of 3971820 is about 158.3664516749.

The spelling of 3971820 in words is "three million, nine hundred seventy-one thousand, eight hundred twenty".