21355511250 has 160 divisors (see below), whose sum is σ = 54527945472. Its totient is φ = 5572800000.

The previous prime is 21355511209. The next prime is 21355511251. The reversal of 21355511250 is 5211555312.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is not an unprimeable number, because it can be changed into a prime (21355511251) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 49548535 + ... + 49548965.

Almost surely, 2^21355511250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21355511250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27263972736).

21355511250 is an abundant number, since it is smaller than the sum of its proper divisors (33172434222).

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

21355511250 is a wasteful number, since it uses less digits than its factorization.

21355511250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710 (or 695 counting only the distinct ones).

The product of its (nonzero) digits is 7500, while the sum is 30.

The spelling of 21355511250 in words is "twenty-one billion, three hundred fifty-five million, five hundred eleven thousand, two hundred fifty".