21881222 has 16 divisors (see below), whose sum is σ = 35903952. Its totient is φ = 9918720.

The previous prime is 21881221. The next prime is 21881243. The reversal of 21881222 is 22218812.

It is a junction number, because it is equal to n+sod(n) for n = 21881191 and 21881200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21881221) 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, 8378 + ... + 10674.

It is an arithmetic number, because the mean of its divisors is an integer number (2243997).

Almost surely, 2^21881222 is an apocalyptic number.

21881222 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21881222 is a deficient number, since it is larger than the sum of its proper divisors (14022730).

21881222 is a wasteful number, since it uses less digits than its factorization.

21881222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2743.

The product of its digits is 1024, while the sum is 26.

The square root of 21881222 is about 4677.7368459545. The cubic root of 21881222 is about 279.6987491309.

The spelling of 21881222 in words is "twenty-one million, eight hundred eighty-one thousand, two hundred twenty-two".