21563290289641 has 3 divisors (see below), whose sum is σ = 21563294933271. Its totient is φ = 21563285646012.

The previous prime is 21563290289621. The next prime is 21563290289677. The reversal of 21563290289641 is 14698209236512.

It is a happy number.

The square root of 21563290289641 is 4643629.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 12946834545241 + 8616455744400 = 3598171^2 + 2935380^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21563290289641 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21563290289621) 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 2 ways as a sum of consecutive naturals, for example, 2321815 + ... + 6965443.

It is an arithmetic number, because the mean of its divisors is an integer number (7187764977757).

Almost surely, 2^{21563290289641} is an apocalyptic number.

21563290289641 is the 4643629-th square number.

21563290289641 is the 2321815-th centered octagonal number.

It is an amenable number.

21563290289641 is a deficient number, since it is larger than the sum of its proper divisors (4643630).

21563290289641 is an frugal number, since it uses more digits than its factorization.

21563290289641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9287258 (or 4643629 counting only the distinct ones).

The product of its (nonzero) digits is 11197440, while the sum is 58.

The spelling of 21563290289641 in words is "twenty-one trillion, five hundred sixty-three billion, two hundred ninety million, two hundred eighty-nine thousand, six hundred forty-one".