21225858 has 16 divisors (see below), whose sum is σ = 43355520. Its totient is φ = 6924656.

The previous prime is 21225851. The next prime is 21225863. The reversal of 21225858 is 85852212.

It is not an unprimeable number, because it can be changed into a prime (21225851) 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, 37353 + ... + 37916.

It is an arithmetic number, because the mean of its divisors is an integer number (2709720).

Almost surely, 2^21225858 is an apocalyptic number.

21225858 is an abundant number, since it is smaller than the sum of its proper divisors (22129662).

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

21225858 is a wasteful number, since it uses less digits than its factorization.

21225858 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75321.

The product of its digits is 12800, while the sum is 33.

The square root of 21225858 is about 4607.1529169325. The cubic root of 21225858 is about 276.8779802039.

The spelling of 21225858 in words is "twenty-one million, two hundred twenty-five thousand, eight hundred fifty-eight".