20212251 has 4 divisors (see below), whose sum is σ = 26949672. Its totient is φ = 13474832.

The previous prime is 20212223. The next prime is 20212259. The reversal of 20212251 is 15221202.

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

It is a cyclic number.

It is not a de Polignac number, because 20212251 - 2⁶ = 20212187 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20212251.

It is not an unprimeable number, because it can be changed into a prime (20212259) 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, 3368706 + ... + 3368711.

It is an arithmetic number, because the mean of its divisors is an integer number (6737418).

Almost surely, 2^20212251 is an apocalyptic number.

20212251 is a deficient number, since it is larger than the sum of its proper divisors (6737421).

20212251 is an equidigital number, since it uses as much as digits as its factorization.

20212251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6737420.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 20212251 is about 4495.8037101279. The cubic root of 20212251 is about 272.3986144733.

Adding to 20212251 its reverse (15221202), we get a palindrome (35433453).

The spelling of 20212251 in words is "twenty million, two hundred twelve thousand, two hundred fifty-one".