19640423 has 16 divisors (see below), whose sum is σ = 22892544. Its totient is φ = 16652160.

The previous prime is 19640399. The next prime is 19640441. The reversal of 19640423 is 32404691.

It is a cyclic number.

It is not a de Polignac number, because 19640423 - 2¹⁸ = 19378279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19640443) 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 15 ways as a sum of consecutive naturals, for example, 23336 + ... + 24162.

It is an arithmetic number, because the mean of its divisors is an integer number (1430784).

Almost surely, 2^19640423 is an apocalyptic number.

19640423 is a deficient number, since it is larger than the sum of its proper divisors (3252121).

19640423 is a wasteful number, since it uses less digits than its factorization.

19640423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 982.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 19640423 is about 4431.7516852820. The cubic root of 19640423 is about 269.8051772433.

The spelling of 19640423 in words is "nineteen million, six hundred forty thousand, four hundred twenty-three".