1690897 has 4 divisors (see below), whose sum is σ = 1820980. Its totient is φ = 1560816.

The previous prime is 1690883. The next prime is 1690901. The reversal of 1690897 is 7980961.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 7980961 = 269 ⋅29669.

It can be written as a sum of positive squares in 2 ways, for example, as 767376 + 923521 = 876^2 + 961^2 .

It is a cyclic number.

It is not a de Polignac number, because 1690897 - 2¹⁹ = 1166609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1690847) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 65022 + ... + 65047.

It is an arithmetic number, because the mean of its divisors is an integer number (455245).

2^1690897 is an apocalyptic number.

It is an amenable number.

1690897 is a deficient number, since it is larger than the sum of its proper divisors (130083).

1690897 is a wasteful number, since it uses less digits than its factorization.

1690897 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130082.

The product of its (nonzero) digits is 27216, while the sum is 40.

The square root of 1690897 is about 1300.3449542333. The cubic root of 1690897 is about 119.1349127798.

Subtracting 1690897 from its reverse (7980961), we obtain a square (6290064 = 2508²).

The spelling of 1690897 in words is "one million, six hundred ninety thousand, eight hundred ninety-seven".