21260057 has 16 divisors (see below), whose sum is σ = 26285952. Its totient is φ = 16744320.

The previous prime is 21260051. The next prime is 21260077. The reversal of 21260057 is 75006212.

It is a cyclic number.

It is not a de Polignac number, because 21260057 - 2⁸ = 21259801 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21260051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27557 + ... + 28317.

It is an arithmetic number, because the mean of its divisors is an integer number (1642872).

Almost surely, 2^21260057 is an apocalyptic number.

It is an amenable number.

21260057 is a deficient number, since it is larger than the sum of its proper divisors (5025895).

21260057 is a wasteful number, since it uses less digits than its factorization.

21260057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1088.

The product of its (nonzero) digits is 840, while the sum is 23.

The square root of 21260057 is about 4610.8629344191. The cubic root of 21260057 is about 277.0266019016.

Adding to 21260057 its reverse (75006212), we get a palindrome (96266269).

The spelling of 21260057 in words is "twenty-one million, two hundred sixty thousand, fifty-seven".