21389526 has 12 divisors (see below), whose sum is σ = 46344012. Its totient is φ = 7129836.

The previous prime is 21389521. The next prime is 21389561. The reversal of 21389526 is 62598312.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21389521) 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 5 ways as a sum of consecutive naturals, for example, 594136 + ... + 594171.

It is an arithmetic number, because the mean of its divisors is an integer number (3862001).

Almost surely, 2^21389526 is an apocalyptic number.

21389526 is an abundant number, since it is smaller than the sum of its proper divisors (24954486).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21389526 is a wasteful number, since it uses less digits than its factorization.

21389526 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1188315 (or 1188312 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 21389526 is about 4624.8811876631. The cubic root of 21389526 is about 277.5878076156.

It can be divided in two parts, 2138 and 9526, that added together give a square (11664 = 108²).

The spelling of 21389526 in words is "twenty-one million, three hundred eighty-nine thousand, five hundred twenty-six".