2091690 has 64 divisors (see below), whose sum is σ = 5713920. Its totient is φ = 544320.

The previous prime is 2091671. The next prime is 2091703. The reversal of 2091690 is 961902.

It is a happy number.

It is a super-2 number, since 2×2091690² = 8750334112200, which contains 22 as substring.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16407 + ... + 16533.

It is an arithmetic number, because the mean of its divisors is an integer number (89280).

2^2091690 is an apocalyptic number.

2091690 is the 915-th heptagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2091690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2856960).

2091690 is an abundant number, since it is smaller than the sum of its proper divisors (3622230).

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

2091690 is a wasteful number, since it uses less digits than its factorization.

2091690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204 (or 198 counting only the distinct ones).

The product of its (nonzero) digits is 972, while the sum is 27.

The square root of 2091690 is about 1446.2676100916. The cubic root of 2091690 is about 127.8887787115. Note that the first 3 decimals are identical.

The spelling of 2091690 in words is "two million, ninety-one thousand, six hundred ninety".