21713235840 has 288 divisors, whose sum is σ = 77873407560. Its totient is φ = 5789076480.

The previous prime is 21713235823. The next prime is 21713235871. The reversal of 21713235840 is 4853231712.

21713235840 is a `hidden beast` number, since 2 + 1 + 71 + 3 + 2 + 3 + 584 + 0 = 666.

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

It is a super-2 number, since 2×21713235840² (a number of 21 digits) contains 22 as substring.

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 = 21713235795 and 21713235804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 4196455 + ... + 4201625.

Almost surely, 2^21713235840 is an apocalyptic number.

21713235840 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 21713235840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38936703780).

21713235840 is an abundant number, since it is smaller than the sum of its proper divisors (56160171720).

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

21713235840 is an frugal number, since it uses more digits than its factorization.

21713235840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5214 (or 5181 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 36.

The spelling of 21713235840 in words is "twenty-one billion, seven hundred thirteen million, two hundred thirty-five thousand, eight hundred forty".