22420021 has 4 divisors (see below), whose sum is σ = 24144652. Its totient is φ = 20695392.

The previous prime is 22420003. The next prime is 22420033. The reversal of 22420021 is 12002422.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1535121 + 20884900 = 1239^2 + 4570^2 .

It is a cyclic number.

It is not a de Polignac number, because 22420021 - 2¹¹ = 22417973 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (13), and also a Moran number because the ratio is a prime number: 1724617 = 22420021 / (2 + 2 + 4 + 2 + 0 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 22419983 and 22420010.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22420421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 862296 + ... + 862321.

It is an arithmetic number, because the mean of its divisors is an integer number (6036163).

Almost surely, 2^22420021 is an apocalyptic number.

It is an amenable number.

22420021 is a deficient number, since it is larger than the sum of its proper divisors (1724631).

22420021 is a wasteful number, since it uses less digits than its factorization.

22420021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1724630.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 22420021 is about 4734.9784582403. The cubic root of 22420021 is about 281.9759087781.

Adding to 22420021 its reverse (12002422), we get a palindrome (34422443).

The spelling of 22420021 in words is "twenty-two million, four hundred twenty thousand, twenty-one".