21001131320540 has 24 divisors (see below), whose sum is σ = 50402715169632. Its totient is φ = 7200387881280.

The previous prime is 21001131320537. The next prime is 21001131320549. The reversal of 21001131320540 is 4502313110012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001131320549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 75004040291 + ... + 75004040570.

It is an arithmetic number, because the mean of its divisors is an integer number (2100113132068).

Almost surely, 2^{21001131320540} is an apocalyptic number.

21001131320540 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001131320540 is an abundant number, since it is smaller than the sum of its proper divisors (29401583849092).

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

21001131320540 is a wasteful number, since it uses less digits than its factorization.

21001131320540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150008080877 (or 150008080875 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 21001131320540 its reverse (4502313110012), we get a palindrome (25503444430552).

The spelling of 21001131320540 in words is "twenty-one trillion, one billion, one hundred thirty-one million, three hundred twenty thousand, five hundred forty".