19640634 has 32 divisors (see below), whose sum is σ = 43110144. Its totient is φ = 5928000.

The previous prime is 19640633. The next prime is 19640651. The reversal of 19640634 is 43604691.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 19640595 and 19640604.

It is not an unprimeable number, because it can be changed into a prime (19640633) 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, 1759 + ... + 6509.

It is an arithmetic number, because the mean of its divisors is an integer number (1347192).

Almost surely, 2^19640634 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19640634, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21555072).

19640634 is an abundant number, since it is smaller than the sum of its proper divisors (23469510).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19640634 is a wasteful number, since it uses less digits than its factorization.

19640634 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4822.

The product of its (nonzero) digits is 15552, while the sum is 33.

The square root of 19640634 is about 4431.7754907035. The cubic root of 19640634 is about 269.8061434256.

The spelling of 19640634 in words is "nineteen million, six hundred forty thousand, six hundred thirty-four".