21531101521440 has 192 divisors, whose sum is σ = 77944995394560. Its totient is φ = 4893900672000.

The previous prime is 21531101521379. The next prime is 21531101521459. The reversal of 21531101521440 is 4412510113512.

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 = 21531101521398 and 21531101521407.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17298186 + ... + 18501065.

It is an arithmetic number, because the mean of its divisors is an integer number (405963517680).

Almost surely, 2^{21531101521440} is an apocalyptic number.

21531101521440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21531101521440 is an abundant number, since it is smaller than the sum of its proper divisors (56413893873120).

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

21531101521440 is a wasteful number, since it uses less digits than its factorization.

21531101521440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35799455 (or 35799447 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 30.

Adding to 21531101521440 its reverse (4412510113512), we get a palindrome (25943611634952).

The spelling of 21531101521440 in words is "twenty-one trillion, five hundred thirty-one billion, one hundred one million, five hundred twenty-one thousand, four hundred forty".