21481155 has 12 divisors (see below), whose sum is σ = 37234080. Its totient is φ = 11456592.

The previous prime is 21481111. The next prime is 21481177. The reversal of 21481155 is 55118412.

It is not a de Polignac number, because 21481155 - 2⁶ = 21481091 is a prime.

It is a super-2 number, since 2×21481155² = 922880040268050, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 238635 + ... + 238724.

It is an arithmetic number, because the mean of its divisors is an integer number (3102840).

Almost surely, 2^21481155 is an apocalyptic number.

21481155 is a deficient number, since it is larger than the sum of its proper divisors (15752925).

21481155 is a wasteful number, since it uses less digits than its factorization.

21481155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 477370 (or 477367 counting only the distinct ones).

The product of its digits is 1600, while the sum is 27.

The square root of 21481155 is about 4634.7766936499. The cubic root of 21481155 is about 277.9836222086.

Adding to 21481155 its reverse (55118412), we get a palindrome (76599567).

The spelling of 21481155 in words is "twenty-one million, four hundred eighty-one thousand, one hundred fifty-five".