21385567 has 16 divisors (see below), whose sum is σ = 25446400. Its totient is φ = 17586720.

The previous prime is 21385549. The next prime is 21385591. The reversal of 21385567 is 76558312.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21385567 is a prime.

It is a super-2 number, since 2×21385567² = 914684951822978, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21385597) 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 15 ways as a sum of consecutive naturals, for example, 29809 + ... + 30517.

It is an arithmetic number, because the mean of its divisors is an integer number (1590400).

Almost surely, 2^21385567 is an apocalyptic number.

21385567 is a deficient number, since it is larger than the sum of its proper divisors (4060833).

21385567 is a wasteful number, since it uses less digits than its factorization.

21385567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 886.

The product of its digits is 50400, while the sum is 37.

The square root of 21385567 is about 4624.4531568608. The cubic root of 21385567 is about 277.5706802618.

It can be divided in two parts, 21385 and 567, that added together give a cube (21952 = 28³).

The spelling of 21385567 in words is "twenty-one million, three hundred eighty-five thousand, five hundred sixty-seven".