21505368 has 32 divisors (see below), whose sum is σ = 56102400. Its totient is φ = 6856608.

The previous prime is 21505349. The next prime is 21505381. The reversal of 21505368 is 86350512.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18928 + ... + 20031.

It is an arithmetic number, because the mean of its divisors is an integer number (1753200).

Almost surely, 2^21505368 is an apocalyptic number.

It is an amenable number.

21505368 is an abundant number, since it is smaller than the sum of its proper divisors (34597032).

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

21505368 is a wasteful number, since it uses less digits than its factorization.

21505368 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38991 (or 38987 counting only the distinct ones).

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

The square root of 21505368 is about 4637.3880579481. The cubic root of 21505368 is about 278.0880282968.

The spelling of 21505368 in words is "twenty-one million, five hundred five thousand, three hundred sixty-eight".