21535227 has 40 divisors (see below), whose sum is σ = 38720000. Its totient is φ = 11652336.

The previous prime is 21535187. The next prime is 21535231. The reversal of 21535227 is 72253512.

It is not a de Polignac number, because 21535227 - 2²² = 17340923 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21535227.

It is not an unprimeable number, because it can be changed into a prime (21535237) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 9774 + ... + 11772.

It is an arithmetic number, because the mean of its divisors is an integer number (968000).

Almost surely, 2^21535227 is an apocalyptic number.

21535227 is a gapful number since it is divisible by the number (27) formed by its first and last digit.

21535227 is a deficient number, since it is larger than the sum of its proper divisors (17184773).

21535227 is a wasteful number, since it uses less digits than its factorization.

21535227 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2037 (or 2028 counting only the distinct ones).

The product of its digits is 4200, while the sum is 27.

The square root of 21535227 is about 4640.6063181442. The cubic root of 21535227 is about 278.2166719987.

Adding to 21535227 its reverse (72253512), we get a palindrome (93788739).

The spelling of 21535227 in words is "twenty-one million, five hundred thirty-five thousand, two hundred twenty-seven".