1691289 has 6 divisors (see below), whose sum is σ = 2442986. Its totient is φ = 1127520.

The previous prime is 1691273. The next prime is 1691293. The reversal of 1691289 is 9821961.

It can be written as a sum of positive squares in only one way, i.e., 1172889 + 518400 = 1083^2 + 720^2 .

It is not a de Polignac number, because 1691289 - 2⁴ = 1691273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1691219) 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, 93952 + ... + 93969.

2^1691289 is an apocalyptic number.

It is an amenable number.

1691289 is a deficient number, since it is larger than the sum of its proper divisors (751697).

1691289 is a wasteful number, since it uses less digits than its factorization.

1691289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187927 (or 187924 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 1691289 is about 1300.4956747333. The cubic root of 1691289 is about 119.1441184021.

The spelling of 1691289 in words is "one million, six hundred ninety-one thousand, two hundred eighty-nine".