21351205413440 has 112 divisors (see below), whose sum is σ = 58221301969152. Its totient is φ = 7305859393536.

The previous prime is 21351205413427. The next prime is 21351205413451. The reversal of 21351205413440 is 4431450215312.

It is a tau number, because it is divible by the number of its divisors (112).

It is a super-2 number, since 2×21351205413440² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 21351205413440.

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, 8348219 + ... + 10601658.

It is an arithmetic number, because the mean of its divisors is an integer number (519833053296).

Almost surely, 2^{21351205413440} is an apocalyptic number.

21351205413440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21351205413440 is an abundant number, since it is smaller than the sum of its proper divisors (36870096555712).

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

21351205413440 is a wasteful number, since it uses less digits than its factorization.

21351205413440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18950404 (or 18950394 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 35.

Adding to 21351205413440 its reverse (4431450215312), we get a palindrome (25782655628752).

The spelling of 21351205413440 in words is "twenty-one trillion, three hundred fifty-one billion, two hundred five million, four hundred thirteen thousand, four hundred forty".