21358605 has 16 divisors (see below), whose sum is σ = 35660160. Its totient is φ = 10895808.

The previous prime is 21358577. The next prime is 21358607. The reversal of 21358605 is 50685312.

It is not a de Polignac number, because 21358605 - 2¹⁴ = 21342221 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21358607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30610 + ... + 31299.

It is an arithmetic number, because the mean of its divisors is an integer number (2228760).

Almost surely, 2^21358605 is an apocalyptic number.

It is an amenable number.

21358605 is a deficient number, since it is larger than the sum of its proper divisors (14301555).

21358605 is a wasteful number, since it uses less digits than its factorization.

21358605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61940.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 21358605 is about 4621.5370819674. The cubic root of 21358605 is about 277.4539814933.

The spelling of 21358605 in words is "twenty-one million, three hundred fifty-eight thousand, six hundred five".