2157988 has 24 divisors (see below), whose sum is σ = 4434752. Its totient is φ = 899424.

The previous prime is 2157923. The next prime is 2157989. The reversal of 2157988 is 8897512.

It is a self number, because there is not a number n which added to its sum of digits gives 2157988.

It is not an unprimeable number, because it can be changed into a prime (2157989) 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, 6 + ... + 2077.

2^2157988 is an apocalyptic number.

2157988 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2157988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2217376).

2157988 is an abundant number, since it is smaller than the sum of its proper divisors (2276764).

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

2157988 is a wasteful number, since it uses less digits than its factorization.

2157988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2131 (or 2129 counting only the distinct ones).

The product of its digits is 40320, while the sum is 40.

The square root of 2157988 is about 1469.0091898964. The cubic root of 2157988 is about 129.2259326130.

The spelling of 2157988 in words is "two million, one hundred fifty-seven thousand, nine hundred eighty-eight".