2157890 has 32 divisors (see below), whose sum is σ = 4596480. Its totient is φ = 713664.

The previous prime is 2157863. The next prime is 2157893. The reversal of 2157890 is 987512.

It is not an unprimeable number, because it can be changed into a prime (2157893) 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, 1499 + ... + 2561.

It is an arithmetic number, because the mean of its divisors is an integer number (143640).

2^2157890 is an apocalyptic number.

2157890 is an abundant number, since it is smaller than the sum of its proper divisors (2438590).

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

2157890 is a wasteful number, since it uses less digits than its factorization.

2157890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 2157890 is about 1468.9758337018. The cubic root of 2157890 is about 129.2239764185.

The spelling of 2157890 in words is "two million, one hundred fifty-seven thousand, eight hundred ninety".