21500090040 has 256 divisors, whose sum is σ = 77627289600. Its totient is φ = 4693708800.

The previous prime is 21500090033. The next prime is 21500090041. The reversal of 21500090040 is 4009000512.

It is a junction number, because it is equal to n+sod(n) for n = 21500089989 and 21500090016.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500090041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 688281 + ... + 718839.

It is an arithmetic number, because the mean of its divisors is an integer number (303231600).

Almost surely, 2^21500090040 is an apocalyptic number.

21500090040 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 21500090040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38813644800).

21500090040 is an abundant number, since it is smaller than the sum of its proper divisors (56127199560).

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

21500090040 is a wasteful number, since it uses less digits than its factorization.

21500090040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30638 (or 30634 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 21.

Adding to 21500090040 its reverse (4009000512), we get a palindrome (25509090552).

The spelling of 21500090040 in words is "twenty-one billion, five hundred million, ninety thousand, forty".