19138681 has 4 divisors (see below), whose sum is σ = 20146000. Its totient is φ = 18131364.

The previous prime is 19138673. The next prime is 19138699. The reversal of 19138681 is 18683191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19138681 - 2³ = 19138673 is a prime.

It is a super-2 number, since 2×19138681² = 732578220839522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19138681.

It is not an unprimeable number, because it can be changed into a prime (19138631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 503631 + ... + 503668.

It is an arithmetic number, because the mean of its divisors is an integer number (5036500).

Almost surely, 2^19138681 is an apocalyptic number.

It is an amenable number.

19138681 is a deficient number, since it is larger than the sum of its proper divisors (1007319).

19138681 is a wasteful number, since it uses less digits than its factorization.

19138681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1007318.

The product of its digits is 10368, while the sum is 37.

The square root of 19138681 is about 4374.7778229300. Note that the first 3 decimals coincide. The cubic root of 19138681 is about 267.4878138100.

The spelling of 19138681 in words is "nineteen million, one hundred thirty-eight thousand, six hundred eighty-one".