21210267744 has 96 divisors (see below), whose sum is σ = 61964784000. Its totient is φ = 7058489472.

The previous prime is 21210267733. The next prime is 21210267761. The reversal of 21210267744 is 44776201212.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21210267699 and 21210267708.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 514987 + ... + 554645.

It is an arithmetic number, because the mean of its divisors is an integer number (645466500).

Almost surely, 2^21210267744 is an apocalyptic number.

21210267744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21210267744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30982392000).

21210267744 is an abundant number, since it is smaller than the sum of its proper divisors (40754516256).

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

21210267744 is a wasteful number, since it uses less digits than its factorization.

21210267744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40297 (or 40283 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 36.

Adding to 21210267744 its reverse (44776201212), we get a palindrome (65986468956).

The spelling of 21210267744 in words is "twenty-one billion, two hundred ten million, two hundred sixty-seven thousand, seven hundred forty-four".