21157282 has 32 divisors (see below), whose sum is σ = 34992000. Its totient is φ = 9554688.

The previous prime is 21157277. The next prime is 21157313. The reversal of 21157282 is 28275112.

It is a self number, because there is not a number n which added to its sum of digits gives 21157282.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106219 + ... + 106417.

It is an arithmetic number, because the mean of its divisors is an integer number (1093500).

Almost surely, 2^21157282 is an apocalyptic number.

21157282 is a deficient number, since it is larger than the sum of its proper divisors (13834718).

21157282 is a wasteful number, since it uses less digits than its factorization.

21157282 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330.

The product of its digits is 2240, while the sum is 28.

The square root of 21157282 is about 4599.7045557296. The cubic root of 21157282 is about 276.5794815687.

The spelling of 21157282 in words is "twenty-one million, one hundred fifty-seven thousand, two hundred eighty-two".