3878721 has 48 divisors (see below), whose sum is σ = 7263360. Its totient is φ = 1935360.

The previous prime is 3878713. The next prime is 3878741. The reversal of 3878721 is 1278783.

It is not a de Polignac number, because 3878721 - 2³ = 3878713 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3878701) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 20001 + ... + 20193.

It is an arithmetic number, because the mean of its divisors is an integer number (151320).

Almost surely, 2^3878721 is an apocalyptic number.

It is an amenable number.

3878721 is a deficient number, since it is larger than the sum of its proper divisors (3384639).

3878721 is a wasteful number, since it uses less digits than its factorization.

3878721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246 (or 243 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 3878721 is about 1969.4468766636. The cubic root of 3878721 is about 157.1192921374.

The spelling of 3878721 in words is "three million, eight hundred seventy-eight thousand, seven hundred twenty-one".