21225658 has 4 divisors (see below), whose sum is σ = 31838490. Its totient is φ = 10612828.

The previous prime is 21225653. The next prime is 21225661. The reversal of 21225658 is 85652212.

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

It can be written as a sum of positive squares in only one way, i.e., 17197609 + 4028049 = 4147^2 + 2007^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21225653) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5306413 + ... + 5306416.

Almost surely, 2^21225658 is an apocalyptic number.

21225658 is a deficient number, since it is larger than the sum of its proper divisors (10612832).

21225658 is a wasteful number, since it uses less digits than its factorization.

21225658 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10612831.

The product of its digits is 9600, while the sum is 31.

The square root of 21225658 is about 4607.1312115024. The cubic root of 21225658 is about 276.8771105764.

The spelling of 21225658 in words is "twenty-one million, two hundred twenty-five thousand, six hundred fifty-eight".