21506143553240 has 16 divisors (see below), whose sum is σ = 48388822994880. Its totient is φ = 8602457421280.

The previous prime is 21506143553197. The next prime is 21506143553243. The reversal of 21506143553240 is 4235534160512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21506143553243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 268826794376 + ... + 268826794455.

It is an arithmetic number, because the mean of its divisors is an integer number (3024301437180).

Almost surely, 2^{21506143553240} is an apocalyptic number.

21506143553240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21506143553240 is an abundant number, since it is smaller than the sum of its proper divisors (26882679441640).

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

21506143553240 is a wasteful number, since it uses less digits than its factorization.

21506143553240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 537653588842 (or 537653588838 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 41.

The spelling of 21506143553240 in words is "twenty-one trillion, five hundred six billion, one hundred forty-three million, five hundred fifty-three thousand, two hundred forty".