6621990 has 32 divisors (see below), whose sum is σ = 15966720. Its totient is φ = 1757664.

The previous prime is 6621961. The next prime is 6621991. The reversal of 6621990 is 991266.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6621991) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8851 + ... + 9569.

It is an arithmetic number, because the mean of its divisors is an integer number (498960).

Almost surely, 2^6621990 is an apocalyptic number.

6621990 is an abundant number, since it is smaller than the sum of its proper divisors (9344730).

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

6621990 is a wasteful number, since it uses less digits than its factorization.

6621990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1036.

The product of its (nonzero) digits is 5832, while the sum is 33.

The square root of 6621990 is about 2573.3227547278. The cubic root of 6621990 is about 187.7858395780.

The spelling of 6621990 in words is "six million, six hundred twenty-one thousand, nine hundred ninety".