1640989 has 8 divisors (see below), whose sum is σ = 1883520. Its totient is φ = 1400496.

The previous prime is 1640971. The next prime is 1641007. The reversal of 1640989 is 9890461.

It is an interprime number because it is at equal distance from previous prime (1640971) and next prime (1641007).

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 1640989 - 2¹³ = 1632797 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1640929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2187 + ... + 2839.

It is an arithmetic number, because the mean of its divisors is an integer number (235440).

2^1640989 is an apocalyptic number.

It is an amenable number.

1640989 is a deficient number, since it is larger than the sum of its proper divisors (242531).

1640989 is an equidigital number, since it uses as much as digits as its factorization.

1640989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1019.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 1640989 is about 1281.0109289151. The cubic root of 1640989 is about 117.9510713549.

The spelling of 1640989 in words is "one million, six hundred forty thousand, nine hundred eighty-nine".