3897821 has 4 divisors (see below), whose sum is σ = 3988512. Its totient is φ = 3807132.

The previous prime is 3897799. The next prime is 3897823. The reversal of 3897821 is 1287983.

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 a de Polignac number, because none of the positive numbers 2^k-3897821 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 (3897823) 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, 45281 + ... + 45366.

It is an arithmetic number, because the mean of its divisors is an integer number (997128).

Almost surely, 2^3897821 is an apocalyptic number.

It is an amenable number.

3897821 is a deficient number, since it is larger than the sum of its proper divisors (90691).

3897821 is an equidigital number, since it uses as much as digits as its factorization.

3897821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90690.

The product of its digits is 24192, while the sum is 38.

The square root of 3897821 is about 1974.2899989617. The cubic root of 3897821 is about 157.3767709989.

The spelling of 3897821 in words is "three million, eight hundred ninety-seven thousand, eight hundred twenty-one".