21224070 has 96 divisors (see below), whose sum is σ = 64247040. Its totient is φ = 4760640.

The previous prime is 21224053. The next prime is 21224081. The reversal of 21224070 is 7042212.

It is a super-2 number, since 2×21224070² = 900922294729800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 36885 + ... + 37455.

It is an arithmetic number, because the mean of its divisors is an integer number (669240).

Almost surely, 2^21224070 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21224070, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32123520).

21224070 is an abundant number, since it is smaller than the sum of its proper divisors (43022970).

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

21224070 is a wasteful number, since it uses less digits than its factorization.

21224070 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650 (or 647 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 18.

The square root of 21224070 is about 4606.9588667580. The cubic root of 21224070 is about 276.8702055401.

Adding to 21224070 its reverse (7042212), we get a palindrome (28266282).

The spelling of 21224070 in words is "twenty-one million, two hundred twenty-four thousand, seventy".