21509282744 has 8 divisors (see below), whose sum is σ = 40329905160. Its totient is φ = 10754641368.

The previous prime is 21509282677. The next prime is 21509282749. The reversal of 21509282744 is 44728290512.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×21509282744² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21509282695 and 21509282704.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21509282749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1344330164 + ... + 1344330179.

It is an arithmetic number, because the mean of its divisors is an integer number (5041238145).

Almost surely, 2^21509282744 is an apocalyptic number.

It is an amenable number.

21509282744 is a deficient number, since it is larger than the sum of its proper divisors (18820622416).

21509282744 is a wasteful number, since it uses less digits than its factorization.

21509282744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2688660349 (or 2688660345 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 44.

The spelling of 21509282744 in words is "twenty-one billion, five hundred nine million, two hundred eighty-two thousand, seven hundred forty-four".