21881241 has 12 divisors (see below), whose sum is σ = 31835440. Its totient is φ = 14481720.

The previous prime is 21881221. The next prime is 21881243. The reversal of 21881241 is 14218812.

It is not a de Polignac number, because 21881241 - 2⁶ = 21881177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21881243) by changing a digit.

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, 7495 + ... + 9996.

Almost surely, 2^21881241 is an apocalyptic number.

It is an amenable number.

21881241 is a deficient number, since it is larger than the sum of its proper divisors (9954199).

21881241 is a wasteful number, since it uses less digits than its factorization.

21881241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17636 (or 17633 counting only the distinct ones).

The product of its digits is 1024, while the sum is 27.

The square root of 21881241 is about 4677.7388768507. The cubic root of 21881241 is about 279.6988300873.

It can be divided in two parts, 21881 and 241, that added together give a palindrome (22122).

The spelling of 21881241 in words is "twenty-one million, eight hundred eighty-one thousand, two hundred forty-one".