21152250 has 192 divisors, whose sum is σ = 70087680. Its totient is φ = 4492800.

The previous prime is 21152239. The next prime is 21152291. The reversal of 21152250 is 5225112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 267711 + ... + 267789.

It is an arithmetic number, because the mean of its divisors is an integer number (365040).

Almost surely, 2^21152250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21152250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35043840).

21152250 is an abundant number, since it is smaller than the sum of its proper divisors (48935430).

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

21152250 is a wasteful number, since it uses less digits than its factorization.

21152250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126 (or 113 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 18.

The square root of 21152250 is about 4599.1575315486. The cubic root of 21152250 is about 276.5575528178.

Adding to 21152250 its reverse (5225112), we get a palindrome (26377362).

The spelling of 21152250 in words is "twenty-one million, one hundred fifty-two thousand, two hundred fifty".