21253001550 has 192 divisors, whose sum is σ = 59679037440. Its totient is φ = 4960368000.

The previous prime is 21253001501. The next prime is 21253001603. The reversal of 21253001550 is 5510035212.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 21253001550.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5035341 + ... + 5039559.

It is an arithmetic number, because the mean of its divisors is an integer number (310828320).

Almost surely, 2^21253001550 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21253001550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29839518720).

21253001550 is an abundant number, since it is smaller than the sum of its proper divisors (38426035890).

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

21253001550 is a wasteful number, since it uses less digits than its factorization.

21253001550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4359 (or 4354 counting only the distinct ones).

The product of its (nonzero) digits is 1500, while the sum is 24.

Adding to 21253001550 its reverse (5510035212), we get a palindrome (26763036762).

The spelling of 21253001550 in words is "twenty-one billion, two hundred fifty-three million, one thousand, five hundred fifty".