1690 has 12 divisors (see below), whose sum is σ = 3294. Its totient is φ = 624.

The previous prime is 1669. The next prime is 1693. The reversal of 1690 is 961.

1690 is an esthetic number in base 8, because in such base its adjacent digits differ by 1.

It can be written as a sum of positive squares in 3 ways, for example, as 729 + 961 = 27^2 + 31^2 .

It is a super-2 number, since 2×1690² = 5712200, which contains 22 as substring.

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

1690 is an undulating number in base 8.

It is a plaindrome in base 9, base 14, base 15 and base 16.

It is a nialpdrome in base 13.

It is a zygodrome in base 9.

It is not an unprimeable number, because it can be changed into a prime (1693) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 124 + ... + 136.

2¹⁶⁹⁰ is an apocalyptic number.

1690 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1690 is a deficient number, since it is larger than the sum of its proper divisors (1604).

1690 is a wasteful number, since it uses less digits than its factorization.

1690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33 (or 20 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 16.

The square root of 1690 is about 41.1096095822. The cubic root of 1690 is about 11.9113842520.

Subtracting from 1690 its reverse (961), we obtain a 6-th power (729 = 3⁶).

The spelling of 1690 in words is "one thousand, six hundred ninety".