21224541 has 12 divisors (see below), whose sum is σ = 30644448. Its totient is φ = 13060944.

The previous prime is 21224521. The next prime is 21224557. The reversal of 21224541 is 14542212.

It is not a de Polignac number, because 21224541 - 2⁵ = 21224509 is a prime.

It is a super-2 number, since 2×21224541² = 900962281321362, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 20425 + ... + 21438.

It is an arithmetic number, because the mean of its divisors is an integer number (2553704).

Almost surely, 2^21224541 is an apocalyptic number.

It is an amenable number.

21224541 is a deficient number, since it is larger than the sum of its proper divisors (9419907).

21224541 is a wasteful number, since it uses less digits than its factorization.

21224541 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41892 (or 41879 counting only the distinct ones).

The product of its digits is 640, while the sum is 21.

The square root of 21224541 is about 4607.0099847949. The cubic root of 21224541 is about 276.8722536063.

Adding to 21224541 its reverse (14542212), we get a palindrome (35766753).

It can be divided in two parts, 212 and 24541, that added together give a triangular number (24753 = T₂₂₂).

The spelling of 21224541 in words is "twenty-one million, two hundred twenty-four thousand, five hundred forty-one".