1991502 has 48 divisors (see below), whose sum is σ = 4612608. Its totient is φ = 619920.

The previous prime is 1991491. The next prime is 1991503. The reversal of 1991502 is 2051991.

It is a happy number.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1991503) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23953 + ... + 24035.

It is an arithmetic number, because the mean of its divisors is an integer number (96096).

2^1991502 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1991502, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2306304).

1991502 is an abundant number, since it is smaller than the sum of its proper divisors (2621106).

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

1991502 is a wasteful number, since it uses less digits than its factorization.

1991502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 810, while the sum is 27.

The square root of 1991502 is about 1411.2058673347. The cubic root of 1991502 is about 125.8134048330.

The spelling of 1991502 in words is "one million, nine hundred ninety-one thousand, five hundred two".