21131253 has 48 divisors (see below), whose sum is σ = 37068480. Its totient is φ = 11793600.

The previous prime is 21131251. The next prime is 21131269. The reversal of 21131253 is 35213112.

It is not a de Polignac number, because 21131253 - 2¹ = 21131251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21131251) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 49983 + ... + 50403.

It is an arithmetic number, because the mean of its divisors is an integer number (772260).

Almost surely, 2^21131253 is an apocalyptic number.

It is an amenable number.

21131253 is a deficient number, since it is larger than the sum of its proper divisors (15937227).

21131253 is a wasteful number, since it uses less digits than its factorization.

21131253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 467 (or 448 counting only the distinct ones).

The product of its digits is 180, while the sum is 18.

The square root of 21131253 is about 4596.8742641060. The cubic root of 21131253 is about 276.4660132823.

Adding to 21131253 its reverse (35213112), we get a palindrome (56344365).

The spelling of 21131253 in words is "twenty-one million, one hundred thirty-one thousand, two hundred fifty-three".