21521113040 has 80 divisors (see below), whose sum is σ = 60194421120. Its totient is φ = 6990312960.

The previous prime is 21521112941. The next prime is 21521113049. The reversal of 21521113040 is 4031112512.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21521113049) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1000691 + ... + 1021970.

It is an arithmetic number, because the mean of its divisors is an integer number (752430264).

Almost surely, 2^21521113040 is an apocalyptic number.

21521113040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21521113040 is an abundant number, since it is smaller than the sum of its proper divisors (38673308080).

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

21521113040 is a wasteful number, since it uses less digits than its factorization.

21521113040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2022700 (or 2022694 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

Adding to 21521113040 its reverse (4031112512), we get a palindrome (25552225552).

The spelling of 21521113040 in words is "twenty-one billion, five hundred twenty-one million, one hundred thirteen thousand, forty".