21843256530 has 64 divisors (see below), whose sum is σ = 53704747008. Its totient is φ = 5682855360.

The previous prime is 21843256517. The next prime is 21843256543. The reversal of 21843256530 is 3565234812.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21843256517) and next prime (21843256543).

It is a Curzon number.

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, 1165897 + ... + 1184483.

It is an arithmetic number, because the mean of its divisors is an integer number (839136672).

Almost surely, 2^21843256530 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21843256530, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26852373504).

21843256530 is an abundant number, since it is smaller than the sum of its proper divisors (31861490478).

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

21843256530 is a wasteful number, since it uses less digits than its factorization.

21843256530 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19551.

The product of its (nonzero) digits is 172800, while the sum is 39.

The spelling of 21843256530 in words is "twenty-one billion, eight hundred forty-three million, two hundred fifty-six thousand, five hundred thirty".