22212781 has 4 divisors (see below), whose sum is σ = 22235200. Its totient is φ = 22190364.

The previous prime is 22212763. The next prime is 22212787. The reversal of 22212781 is 18721222.

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 not a de Polignac number, because 22212781 - 2¹⁵ = 22180013 is a prime.

It is a super-2 number, since 2×22212781² = 986815279507922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22212787) 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, 9651 + ... + 11728.

It is an arithmetic number, because the mean of its divisors is an integer number (5558800).

Almost surely, 2^22212781 is an apocalyptic number.

It is an amenable number.

22212781 is a deficient number, since it is larger than the sum of its proper divisors (22419).

22212781 is a wasteful number, since it uses less digits than its factorization.

22212781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22418.

The product of its digits is 896, while the sum is 25.

The square root of 22212781 is about 4713.0437086876. The cubic root of 22212781 is about 281.1044009512.

It can be divided in two parts, 222 and 12781, that multiplied together give a palindrome (2837382).

The spelling of 22212781 in words is "twenty-two million, two hundred twelve thousand, seven hundred eighty-one".