2181690 has 48 divisors (see below), whose sum is σ = 6484608. Its totient is φ = 498528.

The previous prime is 2181689. The next prime is 2181709. The reversal of 2181690 is 961812.

It is a super-2 number, since 2×2181690² = 9519542512200, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1102 + ... + 2361.

It is an arithmetic number, because the mean of its divisors is an integer number (135096).

2^2181690 is an apocalyptic number.

2181690 is an abundant number, since it is smaller than the sum of its proper divisors (4302918).

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

2181690 is a wasteful number, since it uses less digits than its factorization.

2181690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3483 (or 3480 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 27.

The square root of 2181690 is about 1477.0545013641. The cubic root of 2181690 is about 129.6973234442.

The spelling of 2181690 in words is "two million, one hundred eighty-one thousand, six hundred ninety".