21225513 has 8 divisors (see below), whose sum is σ = 28341376. Its totient is φ = 14130000.

The previous prime is 21225511. The next prime is 21225541. The reversal of 21225513 is 31552212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21225513 - 2¹ = 21225511 is a prime.

It is a super-2 number, since 2×21225513² = 901044804226338, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21225513.

It is not an unprimeable number, because it can be changed into a prime (21225511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2458 + ... + 6963.

It is an arithmetic number, because the mean of its divisors is an integer number (3542672).

Almost surely, 2^21225513 is an apocalyptic number.

It is an amenable number.

21225513 is a deficient number, since it is larger than the sum of its proper divisors (7115863).

21225513 is an equidigital number, since it uses as much as digits as its factorization.

21225513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10175.

The product of its digits is 600, while the sum is 21.

The square root of 21225513 is about 4607.1154750017. The cubic root of 21225513 is about 276.8764800930.

Adding to 21225513 its reverse (31552212), we get a palindrome (52777725).

The spelling of 21225513 in words is "twenty-one million, two hundred twenty-five thousand, five hundred thirteen".