21144340056 has 96 divisors (see below), whose sum is σ = 61961042880. Its totient is φ = 5995080000.

The previous prime is 21144340043. The next prime is 21144340069. The reversal of 21144340056 is 65004344112.

It is an interprime number because it is at equal distance from previous prime (21144340043) and next prime (21144340069).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 85431 + ... + 222681.

It is an arithmetic number, because the mean of its divisors is an integer number (645427530).

Almost surely, 2^21144340056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21144340056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30980521440).

21144340056 is an abundant number, since it is smaller than the sum of its proper divisors (40816702824).

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

21144340056 is a wasteful number, since it uses less digits than its factorization.

21144340056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137405 (or 137394 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21144340056 its reverse (65004344112), we get a palindrome (86148684168).

The spelling of 21144340056 in words is "twenty-one billion, one hundred forty-four million, three hundred forty thousand, fifty-six".