21500133 has 8 divisors (see below), whose sum is σ = 28689696. Its totient is φ = 14322000.

The previous prime is 21500111. The next prime is 21500137. The reversal of 21500133 is 33100512.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21500133 - 2⁶ = 21500069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500137) 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, 3658 + ... + 7508.

It is an arithmetic number, because the mean of its divisors is an integer number (3586212).

Almost surely, 2^21500133 is an apocalyptic number.

It is an amenable number.

21500133 is a deficient number, since it is larger than the sum of its proper divisors (7189563).

21500133 is a wasteful number, since it uses less digits than its factorization.

21500133 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5715.

The product of its (nonzero) digits is 90, while the sum is 15.

The square root of 21500133 is about 4636.8235894845. The cubic root of 21500133 is about 278.0654616990.

Adding to 21500133 its reverse (33100512), we get a palindrome (54600645).

The spelling of 21500133 in words is "twenty-one million, five hundred thousand, one hundred thirty-three".