21295237 has 4 divisors (see below), whose sum is σ = 22547916. Its totient is φ = 20042560.

The previous prime is 21295231. The next prime is 21295249. The reversal of 21295237 is 73259212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16273156 + 5022081 = 4034^2 + 2241^2 .

It is a cyclic number.

It is not a de Polignac number, because 21295237 - 2¹⁵ = 21262469 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21295199 and 21295208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21295231) 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, 626314 + ... + 626347.

It is an arithmetic number, because the mean of its divisors is an integer number (5636979).

Almost surely, 2^21295237 is an apocalyptic number.

It is an amenable number.

21295237 is a deficient number, since it is larger than the sum of its proper divisors (1252679).

21295237 is a wasteful number, since it uses less digits than its factorization.

21295237 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1252678.

The product of its digits is 7560, while the sum is 31.

The square root of 21295237 is about 4614.6762616678. The cubic root of 21295237 is about 277.1793206076.

The spelling of 21295237 in words is "twenty-one million, two hundred ninety-five thousand, two hundred thirty-seven".