21125236 has 24 divisors (see below), whose sum is σ = 40529664. Its totient is φ = 9554880.

The previous prime is 21125233. The next prime is 21125239. The reversal of 21125236 is 63252112.

It is an interprime number because it is at equal distance from previous prime (21125233) and next prime (21125239).

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21125233) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8736 + ... + 10888.

It is an arithmetic number, because the mean of its divisors is an integer number (1688736).

Almost surely, 2^21125236 is an apocalyptic number.

It is an amenable number.

21125236 is a deficient number, since it is larger than the sum of its proper divisors (19404428).

21125236 is a wasteful number, since it uses less digits than its factorization.

21125236 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2391 (or 2389 counting only the distinct ones).

The product of its digits is 720, while the sum is 22.

The square root of 21125236 is about 4596.2197510563. The cubic root of 21125236 is about 276.4397701009.

Adding to 21125236 its reverse (63252112), we get a palindrome (84377348).

The spelling of 21125236 in words is "twenty-one million, one hundred twenty-five thousand, two hundred thirty-six".