1636989 has 4 divisors (see below), whose sum is σ = 2182656. Its totient is φ = 1091324.

The previous prime is 1636969. The next prime is 1636997. The reversal of 1636989 is 9896361.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1636989 - 2¹² = 1632893 is a prime.

It is a super-2 number, since 2×1636989² = 5359465972242, which contains 22 as substring.

It is a D-number.

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

It is a self number, because there is not a number n which added to its sum of digits gives 1636989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1636909) 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, 272829 + ... + 272834.

It is an arithmetic number, because the mean of its divisors is an integer number (545664).

2^1636989 is an apocalyptic number.

It is an amenable number.

1636989 is a deficient number, since it is larger than the sum of its proper divisors (545667).

1636989 is an equidigital number, since it uses as much as digits as its factorization.

1636989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 545666.

The product of its digits is 69984, while the sum is 42.

The square root of 1636989 is about 1279.4487094057. The cubic root of 1636989 is about 117.8551559943.

The spelling of 1636989 in words is "one million, six hundred thirty-six thousand, nine hundred eighty-nine".