21226457 has 6 divisors (see below), whose sum is σ = 24692058. Its totient is φ = 18194064.

The previous prime is 21226453. The next prime is 21226481. The reversal of 21226457 is 75462212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 19324816 + 1901641 = 4396^2 + 1379^2 .

It is not a de Polignac number, because 21226457 - 2² = 21226453 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21226451) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 216548 + ... + 216645.

It is an arithmetic number, because the mean of its divisors is an integer number (4115343).

Almost surely, 2^21226457 is an apocalyptic number.

It is an amenable number.

21226457 is a deficient number, since it is larger than the sum of its proper divisors (3465601).

21226457 is an equidigital number, since it uses as much as digits as its factorization.

21226457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433207 (or 433200 counting only the distinct ones).

The product of its digits is 6720, while the sum is 29.

The square root of 21226457 is about 4607.2179240839. The cubic root of 21226457 is about 276.8805847056.

Adding to 21226457 its reverse (75462212), we get a palindrome (96688669).

The spelling of 21226457 in words is "twenty-one million, two hundred twenty-six thousand, four hundred fifty-seven".