21307587840 has 1440 divisors, whose sum is σ = 101288081664. Its totient is φ = 4140564480.

The previous prime is 21307587817. The next prime is 21307587853. The reversal of 21307587840 is 4878570312.

21307587840 is a `hidden beast` number, since 21 + 3 + 0 + 7 + 587 + 8 + 40 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

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

It is a congruent number.

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 159 ways as a sum of consecutive naturals, for example, 135717042 + ... + 135717198.

Almost surely, 2^21307587840 is an apocalyptic number.

21307587840 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 21307587840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50644040832).

21307587840 is an abundant number, since it is smaller than the sum of its proper divisors (79980493824).

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

21307587840 is a wasteful number, since it uses less digits than its factorization.

21307587840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 225 (or 202 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 45.

The spelling of 21307587840 in words is "twenty-one billion, three hundred seven million, five hundred eighty-seven thousand, eight hundred forty".