21388227 has 32 divisors (see below), whose sum is σ = 34804224. Its totient is φ = 11404800.

The previous prime is 21388219. The next prime is 21388249. The reversal of 21388227 is 72288312.

It is not a de Polignac number, because 21388227 - 2³ = 21388219 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21388277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 64452 + ... + 64782.

It is an arithmetic number, because the mean of its divisors is an integer number (1087632).

Almost surely, 2^21388227 is an apocalyptic number.

21388227 is a deficient number, since it is larger than the sum of its proper divisors (13415997).

21388227 is a wasteful number, since it uses less digits than its factorization.

21388227 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 539.

The product of its digits is 10752, while the sum is 33.

The square root of 21388227 is about 4624.7407494907. The cubic root of 21388227 is about 277.5821881384.

The spelling of 21388227 in words is "twenty-one million, three hundred eighty-eight thousand, two hundred twenty-seven".