1640249 has 4 divisors (see below), whose sum is σ = 1766436. Its totient is φ = 1514064.

The previous prime is 1640231. The next prime is 1640263. The reversal of 1640249 is 9420461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 9420461 = 199 ⋅47339.

It can be written as a sum of positive squares in 2 ways, for example, as 283024 + 1357225 = 532^2 + 1165^2 .

It is a cyclic number.

It is not a de Polignac number, because 1640249 - 2²⁰ = 591673 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a plaindrome in base 15.

It is not an unprimeable number, because it can be changed into a prime (1640299) 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, 63074 + ... + 63099.

It is an arithmetic number, because the mean of its divisors is an integer number (441609).

2^1640249 is an apocalyptic number.

It is an amenable number.

1640249 is a deficient number, since it is larger than the sum of its proper divisors (126187).

1640249 is a wasteful number, since it uses less digits than its factorization.

1640249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126186.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 1640249 is about 1280.7220619635. The cubic root of 1640249 is about 117.9333387729.

The spelling of 1640249 in words is "one million, six hundred forty thousand, two hundred forty-nine".