1641690 has 96 divisors (see below), whose sum is σ = 4801680. Its totient is φ = 387072.

The previous prime is 1641659. The next prime is 1641709. The reversal of 1641690 is 961461.

It can be written as a sum of positive squares in 8 ways, for example, as 1306449 + 335241 = 1143^2 + 579^2 .

It is a super-2 number, since 2×1641690² = 5390292112200, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 44352 + ... + 44388.

2^1641690 is an apocalyptic number.

1641690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1641690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2400840).

1641690 is an abundant number, since it is smaller than the sum of its proper divisors (3159990).

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

1641690 is a wasteful number, since it uses less digits than its factorization.

1641690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96 (or 93 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 1641690 is about 1281.2845117303. The cubic root of 1641690 is about 117.9678644657.

The spelling of 1641690 in words is "one million, six hundred forty-one thousand, six hundred ninety".