21860072640 has 560 divisors, whose sum is σ = 89446266624. Its totient is φ = 4964198400.

The previous prime is 21860072639. The next prime is 21860072651. The reversal of 21860072640 is 4627006812.

21860072640 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 0 + 0 + 7 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (560).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21860072595 and 21860072604.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 38283555 + ... + 38284125.

Almost surely, 2^21860072640 is an apocalyptic number.

21860072640 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 21860072640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44723133312).

21860072640 is an abundant number, since it is smaller than the sum of its proper divisors (67586193984).

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

21860072640 is a wasteful number, since it uses less digits than its factorization.

21860072640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 818 (or 799 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The spelling of 21860072640 in words is "twenty-one billion, eight hundred sixty million, seventy-two thousand, six hundred forty".