21523893 has 8 divisors (see below), whose sum is σ = 29398656. Its totient is φ = 13999200.

The previous prime is 21523891. The next prime is 21523897. The reversal of 21523893 is 39832512.

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

It is not a de Polignac number, because 21523893 - 2¹ = 21523891 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523891) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87373 + ... + 87618.

It is an arithmetic number, because the mean of its divisors is an integer number (3674832).

Almost surely, 2^21523893 is an apocalyptic number.

It is an amenable number.

21523893 is a deficient number, since it is larger than the sum of its proper divisors (7874763).

21523893 is a wasteful number, since it uses less digits than its factorization.

21523893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175035.

The product of its digits is 12960, while the sum is 33.

The square root of 21523893 is about 4639.3849807922. The cubic root of 21523893 is about 278.1678549122.

The spelling of 21523893 in words is "twenty-one million, five hundred twenty-three thousand, eight hundred ninety-three".