20213081 has 4 divisors (see below), whose sum is σ = 23100672. Its totient is φ = 17325492.

The previous prime is 20213071. The next prime is 20213099. The reversal of 20213081 is 18031202.

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 a de Polignac number, because none of the positive numbers 2^k-20213081 is a prime.

It is a super-2 number, since 2×20213081² = 817137287025122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20213071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1443785 + ... + 1443798.

It is an arithmetic number, because the mean of its divisors is an integer number (5775168).

Almost surely, 2^20213081 is an apocalyptic number.

It is an amenable number.

20213081 is a deficient number, since it is larger than the sum of its proper divisors (2887591).

20213081 is an equidigital number, since it uses as much as digits as its factorization.

20213081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2887590.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 20213081 is about 4495.8960174808. The cubic root of 20213081 is about 272.4023430330.

Adding to 20213081 its reverse (18031202), we get a palindrome (38244283).

The spelling of 20213081 in words is "twenty million, two hundred thirteen thousand, eighty-one".