21135850 has 24 divisors (see below), whose sum is σ = 41024160. Its totient is φ = 8086320.

The previous prime is 21135841. The next prime is 21135857. The reversal of 21135850 is 5853112.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is not an unprimeable number, because it can be changed into a prime (21135857) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8040 + ... + 10339.

It is an arithmetic number, because the mean of its divisors is an integer number (1709340).

Almost surely, 2^21135850 is an apocalyptic number.

21135850 is a deficient number, since it is larger than the sum of its proper divisors (19888310).

21135850 is a wasteful number, since it uses less digits than its factorization.

21135850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18414 (or 18409 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 21135850 is about 4597.3742505913. The cubic root of 21135850 is about 276.4860597685.

Adding to 21135850 its reverse (5853112), we get a palindrome (26988962).

The spelling of 21135850 in words is "twenty-one million, one hundred thirty-five thousand, eight hundred fifty".