21224490 has 64 divisors (see below), whose sum is σ = 58613760. Its totient is φ = 4818240.

The previous prime is 21224479. The next prime is 21224503. The reversal of 21224490 is 9442212.

It is a self number, because there is not a number n which added to its sum of digits gives 21224490.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 44071 + ... + 44549.

It is an arithmetic number, because the mean of its divisors is an integer number (915840).

Almost surely, 2^21224490 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21224490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29306880).

21224490 is an abundant number, since it is smaller than the sum of its proper divisors (37389270).

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

21224490 is a wasteful number, since it uses less digits than its factorization.

21224490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 707.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 21224490 is about 4607.0044497482. The cubic root of 21224490 is about 276.8720318427.

The spelling of 21224490 in words is "twenty-one million, two hundred twenty-four thousand, four hundred ninety".