1690381 has 16 divisors (see below), whose sum is σ = 2183040. Its totient is φ = 1270080.

The previous prime is 1690357. The next prime is 1690387. The reversal of 1690381 is 1830961.

It is a happy number.

It is not a de Polignac number, because 1690381 - 2⁵ = 1690349 is a prime.

It is a super-2 number, since 2×1690381² = 5714775850322, which contains 22 as substring.

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

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1690387) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1855 + ... + 2611.

It is an arithmetic number, because the mean of its divisors is an integer number (136440).

2^1690381 is an apocalyptic number.

1690381 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1690381 is a deficient number, since it is larger than the sum of its proper divisors (492659).

1690381 is a wasteful number, since it uses less digits than its factorization.

1690381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 804.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 1690381 is about 1300.1465302034. The cubic root of 1690381 is about 119.1227930056.

The spelling of 1690381 in words is "one million, six hundred ninety thousand, three hundred eighty-one".