21383505361 has 9 divisors (see below), whose sum is σ = 21496255131. Its totient is φ = 21271346184.

The previous prime is 21383505359. The next prime is 21383505379. The reversal of 21383505361 is 16350538312.

The square root of 21383505361 is 146231.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 15695328961 + 5688176400 = 125281^2 + 75420^2 .

It is not a de Polignac number, because 21383505361 - 2¹ = 21383505359 is a prime.

It is a super-3 number, since 3×21383505361³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21383505361.

It is not an unprimeable number, because it can be changed into a prime (21383505961) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 51034410 + ... + 51034828.

Almost surely, 2^21383505361 is an apocalyptic number.

21383505361 is the 146231-st square number.

21383505361 is the 73116-th centered octagonal number.

It is an amenable number.

21383505361 is a deficient number, since it is larger than the sum of its proper divisors (112749770).

21383505361 is an frugal number, since it uses more digits than its factorization.

21383505361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1536 (or 768 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 37.

The spelling of 21383505361 in words is "twenty-one billion, three hundred eighty-three million, five hundred five thousand, three hundred sixty-one".