21213378340 has 192 divisors, whose sum is σ = 57033123840. Its totient is φ = 6435394560.

The previous prime is 21213378317. The next prime is 21213378353. The reversal of 21213378340 is 4387331212.

It is a junction number, because it is equal to n+sod(n) for n = 21213378296 and 21213378305.

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 63 ways as a sum of consecutive naturals, for example, 37281576 + ... + 37282144.

It is an arithmetic number, because the mean of its divisors is an integer number (297047520).

Almost surely, 2^21213378340 is an apocalyptic number.

21213378340 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 21213378340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28516561920).

21213378340 is an abundant number, since it is smaller than the sum of its proper divisors (35819745500).

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

21213378340 is a wasteful number, since it uses less digits than its factorization.

21213378340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1202 (or 1200 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 34.

The spelling of 21213378340 in words is "twenty-one billion, two hundred thirteen million, three hundred seventy-eight thousand, three hundred forty".