20099081 has 4 divisors (see below), whose sum is σ = 20119572. Its totient is φ = 20078592.

The previous prime is 20099077. The next prime is 20099089. The reversal of 20099081 is 18099002.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 18139081 + 1960000 = 4259^2 + 1400^2 .

It is a cyclic number.

It is not a de Polignac number, because 20099081 - 2² = 20099077 is a prime.

It is a super-2 number, since 2×20099081² = 807946114089122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20099089) 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, 8696 + ... + 10761.

It is an arithmetic number, because the mean of its divisors is an integer number (5029893).

Almost surely, 2^20099081 is an apocalyptic number.

It is an amenable number.

20099081 is a deficient number, since it is larger than the sum of its proper divisors (20491).

20099081 is a wasteful number, since it uses less digits than its factorization.

20099081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20490.

The product of its (nonzero) digits is 1296, while the sum is 29.

The square root of 20099081 is about 4483.1998617059. The cubic root of 20099081 is about 271.8892688332.

The spelling of 20099081 in words is "twenty million, ninety-nine thousand, eighty-one".