21155122 has 16 divisors (see below), whose sum is σ = 32336280. Its totient is φ = 10378368.

The previous prime is 21155119. The next prime is 21155131. The reversal of 21155122 is 22155112.

It can be written as a sum of positive squares in 4 ways, for example, as 14295961 + 6859161 = 3781^2 + 2619^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21155122.

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 7 ways as a sum of consecutive naturals, for example, 27568 + ... + 28324.

Almost surely, 2^21155122 is an apocalyptic number.

21155122 is a deficient number, since it is larger than the sum of its proper divisors (11181158).

21155122 is a wasteful number, since it uses less digits than its factorization.

21155122 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1005.

The product of its digits is 200, while the sum is 19.

The square root of 21155122 is about 4599.4697520475. The cubic root of 21155122 is about 276.5700690173.

The spelling of 21155122 in words is "twenty-one million, one hundred fifty-five thousand, one hundred twenty-two".