21305134040 has 16 divisors (see below), whose sum is σ = 47936551680. Its totient is φ = 8522053600.

The previous prime is 21305134027. The next prime is 21305134057. The reversal of 21305134040 is 4043150312.

It is a junction number, because it is equal to n+sod(n) for n = 21305133997 and 21305134015.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 266314136 + ... + 266314215.

It is an arithmetic number, because the mean of its divisors is an integer number (2996034480).

Almost surely, 2^21305134040 is an apocalyptic number.

21305134040 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21305134040 is an abundant number, since it is smaller than the sum of its proper divisors (26631417640).

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

21305134040 is a wasteful number, since it uses less digits than its factorization.

21305134040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532628362 (or 532628358 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

Adding to 21305134040 its reverse (4043150312), we get a palindrome (25348284352).

The spelling of 21305134040 in words is "twenty-one billion, three hundred five million, one hundred thirty-four thousand, forty".