21521135250 has 96 divisors (see below), whose sum is σ = 58234101120. Its totient is φ = 5734932000.

The previous prime is 21521135243. The next prime is 21521135287. The reversal of 21521135250 is 5253112512.

21521135250 is a `hidden beast` number, since 2 + 1 + 521 + 135 + 2 + 5 + 0 = 666.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4585405 + ... + 4590095.

It is an arithmetic number, because the mean of its divisors is an integer number (606605220).

Almost surely, 2^21521135250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21521135250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29117050560).

21521135250 is an abundant number, since it is smaller than the sum of its proper divisors (36712965870).

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

21521135250 is a wasteful number, since it uses less digits than its factorization.

21521135250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6753 (or 6740 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

Adding to 21521135250 its reverse (5253112512), we get a palindrome (26774247762).

The spelling of 21521135250 in words is "twenty-one billion, five hundred twenty-one million, one hundred thirty-five thousand, two hundred fifty".