20643390738432 has 624 divisors, whose sum is σ = 76741361049600. Its totient is φ = 5188932403200.

The previous prime is 20643390738431. The next prime is 20643390738461. The reversal of 20643390738432 is 23483709334602.

20643390738432 is a `hidden beast` number, since 2 + 0 + 64 + 33 + 90 + 7 + 38 + 432 = 666.

It is a super-2 number, since 2×20643390738432² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20643390738431) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 87877069 + ... + 88111667.

It is an arithmetic number, because the mean of its divisors is an integer number (122982950400).

Almost surely, 2^{20643390738432} is an apocalyptic number.

20643390738432 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20643390738432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38370680524800).

20643390738432 is an abundant number, since it is smaller than the sum of its proper divisors (56097970311168).

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

20643390738432 is a wasteful number, since it uses less digits than its factorization.

20643390738432 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234678 (or 234653 counting only the distinct ones).

The product of its (nonzero) digits is 15676416, while the sum is 54.

The spelling of 20643390738432 in words is "twenty trillion, six hundred forty-three billion, three hundred ninety million, seven hundred thirty-eight thousand, four hundred thirty-two".