21768222 has 16 divisors (see below), whose sum is σ = 49756032. Its totient is φ = 6219480.

The previous prime is 21768221. The next prime is 21768223. The reversal of 21768222 is 22286712.

It is an interprime number because it is at equal distance from previous prime (21768221) and next prime (21768223).

It is a self number, because there is not a number n which added to its sum of digits gives 21768222.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21768221) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 259104 + ... + 259187.

It is an arithmetic number, because the mean of its divisors is an integer number (3109752).

Almost surely, 2^21768222 is an apocalyptic number.

21768222 is an abundant number, since it is smaller than the sum of its proper divisors (27987810).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21768222 is a wasteful number, since it uses less digits than its factorization.

21768222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 518303.

The product of its digits is 5376, while the sum is 30.

The square root of 21768222 is about 4665.6427209978. The cubic root of 21768222 is about 279.2164402626.

The spelling of 21768222 in words is "twenty-one million, seven hundred sixty-eight thousand, two hundred twenty-two".