21157222 has 8 divisors (see below), whose sum is σ = 33406200. Its totient is φ = 10021824.

The previous prime is 21157207. The next prime is 21157243. The reversal of 21157222 is 22275112.

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

It is a junction number, because it is equal to n+sod(n) for n = 21157193 and 21157202.

It is a congruent number.

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, 278347 + ... + 278422.

It is an arithmetic number, because the mean of its divisors is an integer number (4175775).

Almost surely, 2^21157222 is an apocalyptic number.

21157222 is a deficient number, since it is larger than the sum of its proper divisors (12248978).

21157222 is a wasteful number, since it uses less digits than its factorization.

21157222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 556790.

The product of its digits is 560, while the sum is 22.

The square root of 21157222 is about 4599.6980335670. The cubic root of 21157222 is about 276.5792201176.

The spelling of 21157222 in words is "twenty-one million, one hundred fifty-seven thousand, two hundred twenty-two".