1591990 has 8 divisors (see below), whose sum is σ = 2865600. Its totient is φ = 636792.

The previous prime is 1591981. The next prime is 1592027. The reversal of 1591990 is 991951.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 79590 + ... + 79609.

It is an arithmetic number, because the mean of its divisors is an integer number (358200).

2^1591990 is an apocalyptic number.

1591990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1591990 is a deficient number, since it is larger than the sum of its proper divisors (1273610).

1591990 is a wasteful number, since it uses less digits than its factorization.

1591990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 159206.

The product of its (nonzero) digits is 3645, while the sum is 34.

The square root of 1591990 is about 1261.7408608744. The cubic root of 1591990 is about 116.7652047320.

It can be divided in two parts, 159 and 1990, that multiplied together give a triangular number (316410 = T₇₉₅).

The spelling of 1591990 in words is "one million, five hundred ninety-one thousand, nine hundred ninety".