1639990 has 32 divisors (see below), whose sum is σ = 3413664. Its totient is φ = 560640.

The previous prime is 1639987. The next prime is 1639991. The reversal of 1639990 is 999361.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1639991) 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, 1432 + ... + 2308.

It is an arithmetic number, because the mean of its divisors is an integer number (106677).

2^1639990 is an apocalyptic number.

1639990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1639990 is an abundant number, since it is smaller than the sum of its proper divisors (1773674).

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

1639990 is a wasteful number, since it uses less digits than its factorization.

1639990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 912.

The product of its (nonzero) digits is 13122, while the sum is 37.

The square root of 1639990 is about 1280.6209431366. The cubic root of 1639990 is about 117.9271311091.

It can be divided in two parts, 163 and 9990, that added together give a triangular number (10153 = T₁₄₂).

The spelling of 1639990 in words is "one million, six hundred thirty-nine thousand, nine hundred ninety".