21357267781840 has 720 divisors, whose sum is σ = 58885546708800. Its totient is φ = 7180505874432.

The previous prime is 21357267781727. The next prime is 21357267781847. The reversal of 21357267781840 is 4818776275312.

It is a super-2 number, since 2×21357267781840² (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 (21357267781847) by changing a digit.

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 143 ways as a sum of consecutive naturals, for example, 16963675131 + ... + 16963676389.

It is an arithmetic number, because the mean of its divisors is an integer number (81785481540).

Almost surely, 2^{21357267781840} is an apocalyptic number.

21357267781840 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 21357267781840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29442773354400).

21357267781840 is an abundant number, since it is smaller than the sum of its proper divisors (37528278926960).

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

21357267781840 is a wasteful number, since it uses less digits than its factorization.

21357267781840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1444 (or 1398 counting only the distinct ones).

The product of its (nonzero) digits is 31610880, while the sum is 61.

The spelling of 21357267781840 in words is "twenty-one trillion, three hundred fifty-seven billion, two hundred sixty-seven million, seven hundred eighty-one thousand, eight hundred forty".