21500153440 has 96 divisors (see below), whose sum is σ = 53108649216. Its totient is φ = 8209681920.

The previous prime is 21500153413. The next prime is 21500153443. The reversal of 21500153440 is 4435100512.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500153443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1919055 + ... + 1930225.

It is an arithmetic number, because the mean of its divisors is an integer number (553215096).

Almost surely, 2^21500153440 is an apocalyptic number.

21500153440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21500153440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26554324608).

21500153440 is an abundant number, since it is smaller than the sum of its proper divisors (31608495776).

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

21500153440 is a wasteful number, since it uses less digits than its factorization.

21500153440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11732 (or 11724 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 25.

Adding to 21500153440 its reverse (4435100512), we get a palindrome (25935253952).

The spelling of 21500153440 in words is "twenty-one billion, five hundred million, one hundred fifty-three thousand, four hundred forty".