21225706 has 8 divisors (see below), whose sum is σ = 31935744. Its totient is φ = 10580460.

The previous prime is 21225691. The next prime is 21225713. The reversal of 21225706 is 60752212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15370 + ... + 16693.

It is an arithmetic number, because the mean of its divisors is an integer number (3991968).

Almost surely, 2^21225706 is an apocalyptic number.

21225706 is a deficient number, since it is larger than the sum of its proper divisors (10710038).

21225706 is a wasteful number, since it uses less digits than its factorization.

21225706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32396.

The product of its (nonzero) digits is 1680, while the sum is 25.

The square root of 21225706 is about 4607.1364208150. The cubic root of 21225706 is about 276.8773192875.

Adding to 21225706 its reverse (60752212), we get a palindrome (81977918).

The spelling of 21225706 in words is "twenty-one million, two hundred twenty-five thousand, seven hundred six".