21224881 has 4 divisors (see below), whose sum is σ = 22342000. Its totient is φ = 20107764.

The previous prime is 21224867. The next prime is 21224893. The reversal of 21224881 is 18842212.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21224881 - 2⁵ = 21224849 is a prime.

It is a super-2 number, since 2×21224881² = 900991146928322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21224821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 558531 + ... + 558568.

It is an arithmetic number, because the mean of its divisors is an integer number (5585500).

Almost surely, 2^21224881 is an apocalyptic number.

It is an amenable number.

21224881 is a deficient number, since it is larger than the sum of its proper divisors (1117119).

21224881 is a wasteful number, since it uses less digits than its factorization.

21224881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1117118.

The product of its digits is 2048, while the sum is 28.

The square root of 21224881 is about 4607.0468849362. The cubic root of 21224881 is about 276.8737320217.

The spelling of 21224881 in words is "twenty-one million, two hundred twenty-four thousand, eight hundred eighty-one".