6663990 has 32 divisors (see below), whose sum is σ = 16091136. Its totient is φ = 1766240.

The previous prime is 6663971. The next prime is 6664019. The reversal of 6663990 is 993666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5149 + ... + 6311.

It is an arithmetic number, because the mean of its divisors is an integer number (502848).

Almost surely, 2^6663990 is an apocalyptic number.

6663990 is an abundant number, since it is smaller than the sum of its proper divisors (9427146).

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

6663990 is a wasteful number, since it uses less digits than its factorization.

6663990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1364.

The product of its (nonzero) digits is 52488, while the sum is 39.

The square root of 6663990 is about 2581.4705111622. The cubic root of 6663990 is about 188.1820140067.

It can be divided in two parts, 666 and 3990, that added together give a triangular number (4656 = T₉₆).

The spelling of 6663990 in words is "six million, six hundred sixty-three thousand, nine hundred ninety".