21405041440 has 48 divisors (see below), whose sum is σ = 50578976448. Its totient is φ = 8560397056.

The previous prime is 21405041431. The next prime is 21405041461. The reversal of 21405041440 is 4414050412.

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 7 ways as a sum of consecutive naturals, for example, 1194789 + ... + 1212571.

It is an arithmetic number, because the mean of its divisors is an integer number (1053728676).

Almost surely, 2^21405041440 is an apocalyptic number.

21405041440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21405041440 is an abundant number, since it is smaller than the sum of its proper divisors (29173935008).

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

21405041440 is a wasteful number, since it uses less digits than its factorization.

21405041440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25321 (or 25313 counting only the distinct ones).

The product of its (nonzero) digits is 2560, while the sum is 25.

Adding to 21405041440 its reverse (4414050412), we get a palindrome (25819091852).

The spelling of 21405041440 in words is "twenty-one billion, four hundred five million, forty-one thousand, four hundred forty".