19931904 has 108 divisors (see below), whose sum is σ = 59149272. Its totient is φ = 6451200.

The previous prime is 19931887. The next prime is 19931909. The reversal of 19931904 is 40913991.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (19931909) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94359 + ... + 94569.

Almost surely, 2^19931904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19931904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29574636).

19931904 is an abundant number, since it is smaller than the sum of its proper divisors (39217368).

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

19931904 is a wasteful number, since it uses less digits than its factorization.

19931904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 274 (or 257 counting only the distinct ones).

The product of its (nonzero) digits is 8748, while the sum is 36.

The square root of 19931904 is about 4464.5160991982. The cubic root of 19931904 is about 271.1333430563.

The spelling of 19931904 in words is "nineteen million, nine hundred thirty-one thousand, nine hundred four".