21388059 has 36 divisors (see below), whose sum is σ = 39213720. Its totient is φ = 11108160.

The previous prime is 21388049. The next prime is 21388099. The reversal of 21388059 is 95088312.

It is not a de Polignac number, because 21388059 - 2⁴ = 21388043 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21388009) 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 35 ways as a sum of consecutive naturals, for example, 2647 + ... + 7055.

It is an arithmetic number, because the mean of its divisors is an integer number (1089270).

Almost surely, 2^21388059 is an apocalyptic number.

21388059 is a deficient number, since it is larger than the sum of its proper divisors (17825661).

21388059 is a wasteful number, since it uses less digits than its factorization.

21388059 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4440 (or 4430 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

The square root of 21388059 is about 4624.7225862748. The cubic root of 21388059 is about 277.5814613534.

The spelling of 21388059 in words is "twenty-one million, three hundred eighty-eight thousand, fifty-nine".