21137253 has 24 divisors (see below), whose sum is σ = 31056480. Its totient is φ = 12751200.

The previous prime is 21137251. The next prime is 21137267. The reversal of 21137253 is 35273112.

It is not a de Polignac number, because 21137253 - 2¹ = 21137251 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21137251) 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 23 ways as a sum of consecutive naturals, for example, 29803 + ... + 30503.

It is an arithmetic number, because the mean of its divisors is an integer number (1294020).

Almost surely, 2^21137253 is an apocalyptic number.

21137253 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

21137253 is a deficient number, since it is larger than the sum of its proper divisors (9919227).

21137253 is a wasteful number, since it uses less digits than its factorization.

21137253 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 769 (or 746 counting only the distinct ones).

The product of its digits is 1260, while the sum is 24.

The square root of 21137253 is about 4597.5268351582. The cubic root of 21137253 is about 276.4921773579.

The spelling of 21137253 in words is "twenty-one million, one hundred thirty-seven thousand, two hundred fifty-three".