1988591 has 8 divisors (see below), whose sum is σ = 2180304. Its totient is φ = 1798720.

The previous prime is 1988587. The next prime is 1988599. The reversal of 1988591 is 1958891.

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

It is not a de Polignac number, because 1988591 - 2² = 1988587 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1988599) 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, 2915 + ... + 3531.

It is an arithmetic number, because the mean of its divisors is an integer number (272538).

2^1988591 is an apocalyptic number.

1988591 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1988591 is a deficient number, since it is larger than the sum of its proper divisors (191713).

1988591 is a wasteful number, since it uses less digits than its factorization.

1988591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 921.

The product of its digits is 25920, while the sum is 41.

The square root of 1988591 is about 1410.1741027263. The cubic root of 1988591 is about 125.7520740027.

The spelling of 1988591 in words is "one million, nine hundred eighty-eight thousand, five hundred ninety-one".