21844592640 has 288 divisors, whose sum is σ = 81537707160. Its totient is φ = 5376835584.

The previous prime is 21844592639. The next prime is 21844592641. The reversal of 21844592640 is 4629544812.

It is a happy number.

21844592640 is a `hidden beast` number, since 2 + 18 + 4 + 4 + 592 + 6 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (21844592639) and next prime (21844592641).

It can be written as a sum of positive squares in 4 ways, for example, as 15075910656 + 6768681984 = 122784^2 + 82272^2 .

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (21844592641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1188964 + ... + 1207196.

Almost surely, 2^21844592640 is an apocalyptic number.

21844592640 is a gapful number since it is divisible by the number (20) 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 21844592640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40768853580).

21844592640 is an abundant number, since it is smaller than the sum of its proper divisors (59693114520).

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

21844592640 is a wasteful number, since it uses less digits than its factorization.

21844592640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18279 (or 18256 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 45.

The spelling of 21844592640 in words is "twenty-one billion, eight hundred forty-four million, five hundred ninety-two thousand, six hundred forty".