19138640 has 20 divisors (see below), whose sum is σ = 44497524. Its totient is φ = 7655424.

The previous prime is 19138631. The next prime is 19138661. The reversal of 19138640 is 4683191.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14227984 + 4910656 = 3772^2 + 2216^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 19138597 and 19138606.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 119537 + ... + 119696.

Almost surely, 2^19138640 is an apocalyptic number.

19138640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19138640 is an abundant number, since it is smaller than the sum of its proper divisors (25358884).

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

19138640 is a wasteful number, since it uses less digits than its factorization.

19138640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 239246 (or 239240 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 32.

The square root of 19138640 is about 4374.7731369752. The cubic root of 19138640 is about 267.4876228005.

The spelling of 19138640 in words is "nineteen million, one hundred thirty-eight thousand, six hundred forty".