19904381 has 16 divisors (see below), whose sum is σ = 24182400. Its totient is φ = 16003008.

The previous prime is 19904377. The next prime is 19904413. The reversal of 19904381 is 18340991.

It is not a de Polignac number, because 19904381 - 2² = 19904377 is a prime.

It is a super-2 number, since 2×19904381² = 792368765986322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19904321) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13811 + ... + 15183.

It is an arithmetic number, because the mean of its divisors is an integer number (1511400).

Almost surely, 2^19904381 is an apocalyptic number.

It is an amenable number.

19904381 is a deficient number, since it is larger than the sum of its proper divisors (4278019).

19904381 is a wasteful number, since it uses less digits than its factorization.

19904381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1508.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 19904381 is about 4461.4326174448. The cubic root of 19904381 is about 271.0084872729.

The spelling of 19904381 in words is "nineteen million, nine hundred four thousand, three hundred eighty-one".