21123013344 has 24 divisors (see below), whose sum is σ = 55447910280. Its totient is φ = 7041004416.

The previous prime is 21123013343. The next prime is 21123013391. The reversal of 21123013344 is 44331032112.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (24).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21123013343) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 110015599 + ... + 110015790.

It is an arithmetic number, because the mean of its divisors is an integer number (2310329595).

Almost surely, 2^21123013344 is an apocalyptic number.

21123013344 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21123013344 is an abundant number, since it is smaller than the sum of its proper divisors (34324896936).

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

21123013344 is a wasteful number, since it uses less digits than its factorization.

21123013344 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220031402 (or 220031394 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 24.

Adding to 21123013344 its reverse (44331032112), we get a palindrome (65454045456).

The spelling of 21123013344 in words is "twenty-one billion, one hundred twenty-three million, thirteen thousand, three hundred forty-four".