21530551243040 has 72 divisors (see below), whose sum is σ = 59170568526972. Its totient is φ = 7381903280640.

The previous prime is 21530551243021. The next prime is 21530551243043. The reversal of 21530551243040 is 4034215503512.

It can be written as a sum of positive squares in 2 ways, for example, as 21509522762896 + 21028480144 = 4637836^2 + 145012^2 .

It is a Harshad number since it is a multiple of its sum of digits (35).

It is not an unprimeable number, because it can be changed into a prime (21530551243043) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1373114051 + ... + 1373129730.

Almost surely, 2^{21530551243040} is an apocalyptic number.

21530551243040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21530551243040 is an abundant number, since it is smaller than the sum of its proper divisors (37640017283932).

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

21530551243040 is a wasteful number, since it uses less digits than its factorization.

21530551243040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2746243810 (or 2746243795 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 35.

Adding to 21530551243040 its reverse (4034215503512), we get a palindrome (25564766746552).

The spelling of 21530551243040 in words is "twenty-one trillion, five hundred thirty billion, five hundred fifty-one million, two hundred forty-three thousand, forty".