19640249 has 4 divisors (see below), whose sum is σ = 19662720. Its totient is φ = 19617780.

The previous prime is 19640237. The next prime is 19640297. The reversal of 19640249 is 94204691.

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 19640249 - 2¹² = 19636153 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (19640209) 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, 9869 + ... + 11690.

It is an arithmetic number, because the mean of its divisors is an integer number (4915680).

Almost surely, 2^19640249 is an apocalyptic number.

It is an amenable number.

19640249 is a deficient number, since it is larger than the sum of its proper divisors (22471).

19640249 is an equidigital number, since it uses as much as digits as its factorization.

19640249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22470.

The product of its (nonzero) digits is 15552, while the sum is 35.

The square root of 19640249 is about 4431.7320541748. The cubic root of 19640249 is about 269.8043804811.

The spelling of 19640249 in words is "nineteen million, six hundred forty thousand, two hundred forty-nine".