21022155 has 48 divisors (see below), whose sum is σ = 45437184. Its totient is φ = 8735040.

The previous prime is 21022117. The next prime is 21022163. The reversal of 21022155 is 55122012.

It is not a de Polignac number, because 21022155 - 2⁶ = 21022091 is a prime.

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 47 ways as a sum of consecutive naturals, for example, 432 + ... + 6498.

It is an arithmetic number, because the mean of its divisors is an integer number (946608).

Almost surely, 2^21022155 is an apocalyptic number.

21022155 is an abundant number, since it is smaller than the sum of its proper divisors (24415029).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21022155 is a wasteful number, since it uses less digits than its factorization.

21022155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6096 (or 6093 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21022155 is about 4584.9923664059. The cubic root of 21022155 is about 275.9894057055.

Adding to 21022155 its reverse (55122012), we get a palindrome (76144167).

It can be divided in two parts, 210221 and 55, that added together give a triangular number (210276 = T₆₄₈).

The spelling of 21022155 in words is "twenty-one million, twenty-two thousand, one hundred fifty-five".