251988 has 48 divisors (see below), whose sum is σ = 677376. Its totient is φ = 72160.

The previous prime is 251983. The next prime is 252001. The reversal of 251988 is 889152.

It is a happy number.

251988 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (251983) by changing a digit.

251988 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2995 + ... + 3077.

It is an arithmetic number, because the mean of its divisors is an integer number (14112).

2²⁵¹⁹⁸⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 251988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (338688).

251988 is an abundant number, since it is smaller than the sum of its proper divisors (425388).

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

251988 is a wasteful number, since it uses less digits than its factorization.

251988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124 (or 122 counting only the distinct ones).

The product of its digits is 5760, while the sum is 33.

The square root of 251988 is about 501.9840634921. The cubic root of 251988 is about 63.1625933639.

The spelling of 251988 in words is "two hundred fifty-one thousand, nine hundred eighty-eight".