2661690 has 48 divisors (see below), whose sum is σ = 6808032. Its totient is φ = 665856.

The previous prime is 2661689. The next prime is 2661731. The reversal of 2661690 is 961662.

2661690 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×2661690² = 14169187312200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8517 + ... + 8823.

It is an arithmetic number, because the mean of its divisors is an integer number (141834).

2^2661690 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2661690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3404016).

2661690 is an abundant number, since it is smaller than the sum of its proper divisors (4146342).

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

2661690 is a wasteful number, since it uses less digits than its factorization.

2661690 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 351 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 30.

The square root of 2661690 is about 1631.4686635054. The cubic root of 2661690 is about 138.5859354514.

It can be divided in two parts, 26 and 61690, that added together give a palindrome (61716).

The spelling of 2661690 in words is "two million, six hundred sixty-one thousand, six hundred ninety".