21102250 has 64 divisors (see below), whose sum is σ = 43819776. Its totient is φ = 7560000.

The previous prime is 21102239. The next prime is 21102251. The reversal of 21102250 is 5220112.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a self number, because there is not a number n which added to its sum of digits gives 21102250.

It is not an unprimeable number, because it can be changed into a prime (21102251) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 139675 + ... + 139825.

It is an arithmetic number, because the mean of its divisors is an integer number (684684).

Almost surely, 2^21102250 is an apocalyptic number.

21102250 is an abundant number, since it is smaller than the sum of its proper divisors (22717526).

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

21102250 is a wasteful number, since it uses less digits than its factorization.

21102250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224 (or 214 counting only the distinct ones).

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 21102250 is about 4593.7185373072. The cubic root of 21102250 is about 276.3394706203.

Adding to 21102250 its reverse (5220112), we get a palindrome (26322362).

The spelling of 21102250 in words is "twenty-one million, one hundred two thousand, two hundred fifty".