21500512 has 48 divisors (see below), whose sum is σ = 48907152. Its totient is φ = 9195520.

The previous prime is 21500509. The next prime is 21500519.

21500512 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4188 + ... + 7780.

It is an arithmetic number, because the mean of its divisors is an integer number (1018899).

Almost surely, 2^21500512 is an apocalyptic number.

21500512 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21500512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24453576).

21500512 is an abundant number, since it is smaller than the sum of its proper divisors (27406640).

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

21500512 is a wasteful number, since it uses less digits than its factorization.

21500512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3631 (or 3623 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21500512 is about 4636.8644577990. The cubic root of 21500512 is about 278.0670955833.

The spelling of 21500512 in words is "twenty-one million, five hundred thousand, five hundred twelve".