21230253 has 24 divisors (see below), whose sum is σ = 33729696. Its totient is φ = 12760800.

The previous prime is 21230249. The next prime is 21230273. The reversal of 21230253 is 35203212.

It is not a de Polignac number, because 21230253 - 2² = 21230249 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21230203) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12151 + ... + 13787.

It is an arithmetic number, because the mean of its divisors is an integer number (1405404).

Almost surely, 2^21230253 is an apocalyptic number.

It is an amenable number.

21230253 is a deficient number, since it is larger than the sum of its proper divisors (12499443).

21230253 is a wasteful number, since it uses less digits than its factorization.

21230253 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1785 (or 1782 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 21230253 is about 4607.6298679473. The cubic root of 21230253 is about 276.8970888896.

Adding to 21230253 its reverse (35203212), we get a palindrome (56433465).

The spelling of 21230253 in words is "twenty-one million, two hundred thirty thousand, two hundred fifty-three".