22021840 has 40 divisors (see below), whose sum is σ = 51568128. Its totient is φ = 8745600.

The previous prime is 22021829. The next prime is 22021847. The reversal of 22021840 is 4812022.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×22021840² = 969922873971200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22021847) 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, 11169 + ... + 12991.

Almost surely, 2^22021840 is an apocalyptic number.

22021840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 22021840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25784064).

22021840 is an abundant number, since it is smaller than the sum of its proper divisors (29546288).

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

22021840 is a wasteful number, since it uses less digits than its factorization.

22021840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1987 (or 1981 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

The square root of 22021840 is about 4692.7433341277. The cubic root of 22021840 is about 280.2966244286.

Adding to 22021840 its reverse (4812022), we get a palindrome (26833862).

The spelling of 22021840 in words is "twenty-two million, twenty-one thousand, eight hundred forty".