21213415305640 has 64 divisors (see below), whose sum is σ = 48549149625600. Its totient is φ = 8339831447808.

The previous prime is 21213415305631. The next prime is 21213415305653. The reversal of 21213415305640 is 4650351431212.

It is a super-2 number, since 2×21213415305640² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21213415305640.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10588177 + ... + 12431263.

It is an arithmetic number, because the mean of its divisors is an integer number (758580462900).

Almost surely, 2^{21213415305640} is an apocalyptic number.

21213415305640 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 21213415305640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24274574812800).

21213415305640 is an abundant number, since it is smaller than the sum of its proper divisors (27335734319960).

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

21213415305640 is a wasteful number, since it uses less digits than its factorization.

21213415305640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1848034 (or 1848030 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 37.

Adding to 21213415305640 its reverse (4650351431212), we get a palindrome (25863766736852).

The spelling of 21213415305640 in words is "twenty-one trillion, two hundred thirteen billion, four hundred fifteen million, three hundred five thousand, six hundred forty".