2157138 has 32 divisors (see below), whose sum is σ = 4910400. Its totient is φ = 701568.

The previous prime is 2157131. The next prime is 2157149. The reversal of 2157138 is 8317512.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (2157131) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1858 + ... + 2786.

It is an arithmetic number, because the mean of its divisors is an integer number (153450).

2^2157138 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2157138, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2455200).

2157138 is an abundant number, since it is smaller than the sum of its proper divisors (2753262).

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

2157138 is a wasteful number, since it uses less digits than its factorization.

2157138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983 (or 977 counting only the distinct ones).

The product of its digits is 1680, while the sum is 27.

The square root of 2157138 is about 1468.7198507544. The cubic root of 2157138 is about 129.2089636482.

It can be divided in two parts, 21571 and 38, that added together give a square (21609 = 147²).

The spelling of 2157138 in words is "two million, one hundred fifty-seven thousand, one hundred thirty-eight".