21224501 has 4 divisors (see below), whose sum is σ = 22341600. Its totient is φ = 20107404.

The previous prime is 21224479. The next prime is 21224503. The reversal of 21224501 is 10542212.

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 a de Polignac number, because none of the positive numbers 2^k-21224501 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21224501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21224503) 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 3 ways as a sum of consecutive naturals, for example, 558521 + ... + 558558.

It is an arithmetic number, because the mean of its divisors is an integer number (5585400).

Almost surely, 2^21224501 is an apocalyptic number.

It is an amenable number.

21224501 is a deficient number, since it is larger than the sum of its proper divisors (1117099).

21224501 is a wasteful number, since it uses less digits than its factorization.

21224501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1117098.

The product of its (nonzero) digits is 160, while the sum is 17.

The square root of 21224501 is about 4607.0056435824. The cubic root of 21224501 is about 276.8720796741.

Adding to 21224501 its reverse (10542212), we get a palindrome (31766713).

The spelling of 21224501 in words is "twenty-one million, two hundred twenty-four thousand, five hundred one".