6840921 has 8 divisors (see below), whose sum is σ = 9249984. Its totient is φ = 4496240.

The previous prime is 6840871. The next prime is 6840929. The reversal of 6840921 is 1290486.

6840921 = T₄₀₃ + T₄₀₄ + ... + T₄₇₃.

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

It is a cyclic number.

It is not a de Polignac number, because 6840921 - 2⁶ = 6840857 is a prime.

6840921 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (6840929) 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, 15846 + ... + 16271.

It is an arithmetic number, because the mean of its divisors is an integer number (1156248).

Almost surely, 2^6840921 is an apocalyptic number.

It is an amenable number.

6840921 is a deficient number, since it is larger than the sum of its proper divisors (2409063).

6840921 is a wasteful number, since it uses less digits than its factorization.

6840921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32191.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 6840921 is about 2615.5154367734. The cubic root of 6840921 is about 189.8329186745.

The spelling of 6840921 in words is "six million, eight hundred forty thousand, nine hundred twenty-one".