21312594 has 48 divisors (see below), whose sum is σ = 49266360. Its totient is φ = 6658560.

The previous prime is 21312587. The next prime is 21312619. The reversal of 21312594 is 49521312.

It can be written as a sum of positive squares in 4 ways, for example, as 20385225 + 927369 = 4515^2 + 963^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 88314 + ... + 88554.

Almost surely, 2^21312594 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21312594, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24633180).

21312594 is an abundant number, since it is smaller than the sum of its proper divisors (27953766).

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

21312594 is a wasteful number, since it uses less digits than its factorization.

21312594 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 300 (or 263 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 21312594 is about 4616.5565089144. The cubic root of 21312594 is about 277.2546065345.

The spelling of 21312594 in words is "twenty-one million, three hundred twelve thousand, five hundred ninety-four".