21523000 has 32 divisors (see below), whose sum is σ = 50366160. Its totient is φ = 8608800.

The previous prime is 21522989. The next prime is 21523001. The reversal of 21523000 is 32512.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21523001) 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, 9762 + ... + 11761.

Almost surely, 2^21523000 is an apocalyptic number.

21523000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21523000 is an abundant number, since it is smaller than the sum of its proper divisors (28843160).

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

21523000 is a wasteful number, since it uses less digits than its factorization.

21523000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21544 (or 21530 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 13.

The square root of 21523000 is about 4639.2887385891. The cubic root of 21523000 is about 278.1640079109.

Adding to 21523000 its reverse (32512), we get a palindrome (21555512).

The spelling of 21523000 in words is "twenty-one million, five hundred twenty-three thousand".