1691491 has 8 divisors (see below), whose sum is σ = 1749440. Its totient is φ = 1634472.

The previous prime is 1691479. The next prime is 1691507. The reversal of 1691491 is 1941961.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1691491 - 2¹³ = 1683299 is a prime.

It is a super-2 number, since 2×1691491² = 5722283606162, which contains 22 as substring.

It is a Duffinian number.

1691491 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1691401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5836 + ... + 6118.

It is an arithmetic number, because the mean of its divisors is an integer number (218680).

2^1691491 is an apocalyptic number.

1691491 is a deficient number, since it is larger than the sum of its proper divisors (57949).

1691491 is a wasteful number, since it uses less digits than its factorization.

1691491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 465.

The product of its digits is 1944, while the sum is 31.

The square root of 1691491 is about 1300.5733351103. The cubic root of 1691491 is about 119.1488615603.

The spelling of 1691491 in words is "one million, six hundred ninety-one thousand, four hundred ninety-one".