21355344 has 30 divisors (see below), whose sum is σ = 59765706. Its totient is φ = 7118400.

The previous prime is 21355291. The next prime is 21355351. The reversal of 21355344 is 44355312.

It can be written as a sum of positive squares in only one way, i.e., 15303744 + 6051600 = 3912^2 + 2460^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 74007 + ... + 74294.

Almost surely, 2^21355344 is an apocalyptic number.

21355344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21355344 is an abundant number, since it is smaller than the sum of its proper divisors (38410362).

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

21355344 is a wasteful number, since it uses less digits than its factorization.

21355344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148315 (or 148306 counting only the distinct ones).

The product of its digits is 7200, while the sum is 27.

The square root of 21355344 is about 4621.1842638008. The cubic root of 21355344 is about 277.4398603544.

The spelling of 21355344 in words is "twenty-one million, three hundred fifty-five thousand, three hundred forty-four".