21225118 has 4 divisors (see below), whose sum is σ = 31837680. Its totient is φ = 10612558.

The previous prime is 21225103. The next prime is 21225119. The reversal of 21225118 is 81152212.

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

It is a super-2 number, since 2×21225118² = 901011268227848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21225119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5306278 + ... + 5306281.

It is an arithmetic number, because the mean of its divisors is an integer number (7959420).

Almost surely, 2^21225118 is an apocalyptic number.

21225118 is a deficient number, since it is larger than the sum of its proper divisors (10612562).

21225118 is a wasteful number, since it uses less digits than its factorization.

21225118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10612561.

The product of its digits is 320, while the sum is 22.

The square root of 21225118 is about 4607.0726063304. The cubic root of 21225118 is about 276.8747625548.

The spelling of 21225118 in words is "twenty-one million, two hundred twenty-five thousand, one hundred eighteen".