19999081 has 4 divisors (see below), whose sum is σ = 20010564. Its totient is φ = 19987600.

The previous prime is 19999069. The next prime is 19999117. The reversal of 19999081 is 18099991.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 13542400 + 6456681 = 3680^2 + 2541^2 .

It is a cyclic number.

It is not a de Polignac number, because 19999081 - 2²¹ = 17901929 is a prime.

It is a super-2 number, since 2×19999081² = 799926481689122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19999481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2530 + ... + 6811.

It is an arithmetic number, because the mean of its divisors is an integer number (5002641).

Almost surely, 2^19999081 is an apocalyptic number.

It is an amenable number.

19999081 is a deficient number, since it is larger than the sum of its proper divisors (11483).

19999081 is an equidigital number, since it uses as much as digits as its factorization.

19999081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11482.

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

The square root of 19999081 is about 4472.0332064957. The cubic root of 19999081 is about 271.4376040128.

The spelling of 19999081 in words is "nineteen million, nine hundred ninety-nine thousand, eighty-one".