21643238430 has 192 divisors, whose sum is σ = 63254131200. Its totient is φ = 5088303360.

The previous prime is 21643238429. The next prime is 21643238431. The reversal of 21643238430 is 3483234612.

21643238430 is a `hidden beast` number, since 2 + 1 + 643 + 2 + 3 + 8 + 4 + 3 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21643238429) and next prime (21643238431).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21643238431) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 13881991 + ... + 13883549.

It is an arithmetic number, because the mean of its divisors is an integer number (329448600).

Almost surely, 2^21643238430 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21643238430, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31627065600).

21643238430 is an abundant number, since it is smaller than the sum of its proper divisors (41610892770).

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

21643238430 is a wasteful number, since it uses less digits than its factorization.

21643238430 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1999 (or 1996 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 36.

The spelling of 21643238430 in words is "twenty-one billion, six hundred forty-three million, two hundred thirty-eight thousand, four hundred thirty".