21453685 has 8 divisors (see below), whose sum is σ = 28084896. Its totient is φ = 15602640.

The previous prime is 21453683. The next prime is 21453703. The reversal of 21453685 is 58635412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21453685 - 2¹ = 21453683 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21453685.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21453683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194979 + ... + 195088.

It is an arithmetic number, because the mean of its divisors is an integer number (3510612).

Almost surely, 2^21453685 is an apocalyptic number.

It is an amenable number.

21453685 is a deficient number, since it is larger than the sum of its proper divisors (6631211).

21453685 is a wasteful number, since it uses less digits than its factorization.

21453685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 390083.

The product of its digits is 28800, while the sum is 34.

The square root of 21453685 is about 4631.8122803067. The cubic root of 21453685 is about 277.8650769462.

The spelling of 21453685 in words is "twenty-one million, four hundred fifty-three thousand, six hundred eighty-five".