21535411440 has 80 divisors (see below), whose sum is σ = 66977463168. Its totient is φ = 5724050688.

The previous prime is 21535411423. The next prime is 21535411441. The reversal of 21535411440 is 4411453512.

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 (30).

It is a junction number, because it is equal to n+sod(n) for n = 21535411398 and 21535411407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21535411441) 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, 72462 + ... + 219821.

Almost surely, 2^21535411440 is an apocalyptic number.

21535411440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21535411440 is an abundant number, since it is smaller than the sum of its proper divisors (45442051728).

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

21535411440 is a wasteful number, since it uses less digits than its factorization.

21535411440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 292606 (or 292600 counting only the distinct ones).

The product of its (nonzero) digits is 9600, while the sum is 30.

Adding to 21535411440 its reverse (4411453512), we get a palindrome (25946864952).

The spelling of 21535411440 in words is "twenty-one billion, five hundred thirty-five million, four hundred eleven thousand, four hundred forty".