19403681 has 12 divisors (see below), whose sum is σ = 22584996. Its totient is φ = 16600320.

The previous prime is 19403627. The next prime is 19403687. The reversal of 19403681 is 18630491.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 14318656 + 5085025 = 3784^2 + 2255^2 .

It is not a de Polignac number, because 19403681 - 2²² = 15209377 is a prime.

It is a super-2 number, since 2×19403681² = 753005672699522, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (19403687) 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, 2660 + ... + 6773.

It is an arithmetic number, because the mean of its divisors is an integer number (1882083).

Almost surely, 2^19403681 is an apocalyptic number.

19403681 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19403681 is a deficient number, since it is larger than the sum of its proper divisors (3181315).

19403681 is a wasteful number, since it uses less digits than its factorization.

19403681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9472 (or 9461 counting only the distinct ones).

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

The square root of 19403681 is about 4404.9609532889. The cubic root of 19403681 is about 268.7167317031.

The spelling of 19403681 in words is "nineteen million, four hundred three thousand, six hundred eighty-one".