21681803424 has 48 divisors (see below), whose sum is σ = 56950296480. Its totient is φ = 7222752000.

The previous prime is 21681803411. The next prime is 21681803497. The reversal of 21681803424 is 42430818612.

It is a tau number, because it is divible by the number of its divisors (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85674 + ... + 225174.

It is an arithmetic number, because the mean of its divisors is an integer number (1186464510).

Almost surely, 2^21681803424 is an apocalyptic number.

21681803424 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21681803424 is an abundant number, since it is smaller than the sum of its proper divisors (35268493056).

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

21681803424 is a wasteful number, since it uses less digits than its factorization.

21681803424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 141133 (or 141125 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 39.

The spelling of 21681803424 in words is "twenty-one billion, six hundred eighty-one million, eight hundred three thousand, four hundred twenty-four".