21502000 has 80 divisors (see below), whose sum is σ = 56058912. Its totient is φ = 7929600.

The previous prime is 21501967. The next prime is 21502001. The reversal of 21502000 is 20512.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21502001) 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 15 ways as a sum of consecutive naturals, for example, 25587 + ... + 26413.

Almost surely, 2^21502000 is an apocalyptic number.

21502000 is a gapful number since it is divisible by the number (20) 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 21502000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28029456).

21502000 is an abundant number, since it is smaller than the sum of its proper divisors (34556912).

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

21502000 is a wasteful number, since it uses less digits than its factorization.

21502000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 863 (or 847 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 21502000 is about 4637.0249082790. The cubic root of 21502000 is about 278.0735102258.

Adding to 21502000 its reverse (20512), we get a palindrome (21522512).

The spelling of 21502000 in words is "twenty-one million, five hundred two thousand".