21227057 has 4 divisors (see below), whose sum is σ = 21284340. Its totient is φ = 21169776.

The previous prime is 21227023. The next prime is 21227081. The reversal of 21227057 is 75072212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 8042896 + 13184161 = 2836^2 + 3631^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21227057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21227257) 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, 28082 + ... + 28827.

It is an arithmetic number, because the mean of its divisors is an integer number (5321085).

Almost surely, 2^21227057 is an apocalyptic number.

It is an amenable number.

21227057 is a deficient number, since it is larger than the sum of its proper divisors (57283).

21227057 is an equidigital number, since it uses as much as digits as its factorization.

21227057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57282.

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 21227057 is about 4607.2830388419. The cubic root of 21227057 is about 276.8831935063.

Adding to 21227057 its reverse (75072212), we get a palindrome (96299269).

The spelling of 21227057 in words is "twenty-one million, two hundred twenty-seven thousand, fifty-seven".