20212091 has 4 divisors (see below), whose sum is σ = 20513832. Its totient is φ = 19910352.

The previous prime is 20212079. The next prime is 20212097. The reversal of 20212091 is 19021202.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20212091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20212097) 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, 150770 + ... + 150903.

It is an arithmetic number, because the mean of its divisors is an integer number (5128458).

Almost surely, 2^20212091 is an apocalyptic number.

20212091 is a deficient number, since it is larger than the sum of its proper divisors (301741).

20212091 is an equidigital number, since it uses as much as digits as its factorization.

20212091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 301740.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 20212091 is about 4495.7859157215. The cubic root of 20212091 is about 272.3978957030.

Adding to 20212091 its reverse (19021202), we get a palindrome (39233293).

The spelling of 20212091 in words is "twenty million, two hundred twelve thousand, ninety-one".