21365420234400 has 432 divisors, whose sum is σ = 82712431253088. Its totient is φ = 5146502400000.

The previous prime is 21365420234399. The next prime is 21365420234407. The reversal of 21365420234400 is 443202456312.

21365420234400 is a `hidden beast` number, since 2 + 1 + 3 + 6 + 5 + 4 + 202 + 3 + 440 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21365420234407) by changing a digit.

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 71 ways as a sum of consecutive naturals, for example, 11575275 + ... + 13293525.

It is an arithmetic number, because the mean of its divisors is an integer number (191463961234).

Almost surely, 2^{21365420234400} is an apocalyptic number.

21365420234400 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 21365420234400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41356215626544).

21365420234400 is an abundant number, since it is smaller than the sum of its proper divisors (61347011018688).

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

21365420234400 is a wasteful number, since it uses less digits than its factorization.

21365420234400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1718445 (or 1718429 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 36.

The spelling of 21365420234400 in words is "twenty-one trillion, three hundred sixty-five billion, four hundred twenty million, two hundred thirty-four thousand, four hundred".