19099981 has 8 divisors (see below), whose sum is σ = 19545624. Its totient is φ = 18657600.

The previous prime is 19099963. The next prime is 19099987. The reversal of 19099981 is 18999091.

It can be written as a sum of positive squares in 4 ways, for example, as 38025 + 19061956 = 195^2 + 4366^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 19099981 - 2⁷ = 19099853 is a prime.

It is a super-2 number, since 2×19099981² = 729618548400722, 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 (19099987) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14031 + ... + 15331.

It is an arithmetic number, because the mean of its divisors is an integer number (2443203).

Almost surely, 2^19099981 is an apocalyptic number.

It is an amenable number.

19099981 is a deficient number, since it is larger than the sum of its proper divisors (445643).

19099981 is a wasteful number, since it uses less digits than its factorization.

19099981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631.

The product of its (nonzero) digits is 52488, while the sum is 46.

The square root of 19099981 is about 4370.3525029453. The cubic root of 19099981 is about 267.3073979700.

The spelling of 19099981 in words is "nineteen million, ninety-nine thousand, nine hundred eighty-one".