21144784020 has 24 divisors (see below), whose sum is σ = 59205395424. Its totient is φ = 5638609056.

The previous prime is 21144783967. The next prime is 21144784039. The reversal of 21144784020 is 2048744112.

It is a congruent number.

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, 176206474 + ... + 176206593.

It is an arithmetic number, because the mean of its divisors is an integer number (2466891476).

Almost surely, 2^21144784020 is an apocalyptic number.

21144784020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21144784020 is an abundant number, since it is smaller than the sum of its proper divisors (38060611404).

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

21144784020 is a wasteful number, since it uses less digits than its factorization.

21144784020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 352413079 (or 352413077 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 33.

The spelling of 21144784020 in words is "twenty-one billion, one hundred forty-four million, seven hundred eighty-four thousand, twenty".