21060253 has 4 divisors (see below), whose sum is σ = 21739648. Its totient is φ = 20380860.

The previous prime is 21060211. The next prime is 21060257. The reversal of 21060253 is 35206012.

It is a happy number.

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 not a de Polignac number, because 21060253 - 2²¹ = 18963101 is a prime.

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 21060253.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21060257) 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, 339651 + ... + 339712.

It is an arithmetic number, because the mean of its divisors is an integer number (5434912).

Almost surely, 2^21060253 is an apocalyptic number.

It is an amenable number.

21060253 is a deficient number, since it is larger than the sum of its proper divisors (679395).

21060253 is an equidigital number, since it uses as much as digits as its factorization.

21060253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 679394.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 21060253 is about 4589.1451273630. The cubic root of 21060253 is about 276.1560283146.

Adding to 21060253 its reverse (35206012), we get a palindrome (56266265).

The spelling of 21060253 in words is "twenty-one million, sixty thousand, two hundred fifty-three".