21683021361 has 4 divisors (see below), whose sum is σ = 28910695152. Its totient is φ = 14455347572.

The previous prime is 21683021359. The next prime is 21683021377. The reversal of 21683021361 is 16312038612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21683021361 - 2¹ = 21683021359 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21683021351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3613836891 + ... + 3613836896.

It is an arithmetic number, because the mean of its divisors is an integer number (7227673788).

Almost surely, 2^21683021361 is an apocalyptic number.

It is an amenable number.

21683021361 is a deficient number, since it is larger than the sum of its proper divisors (7227673791).

21683021361 is an equidigital number, since it uses as much as digits as its factorization.

21683021361 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7227673790.

The product of its (nonzero) digits is 10368, while the sum is 33.

Adding to 21683021361 its reverse (16312038612), we get a palindrome (37995059973).

The spelling of 21683021361 in words is "twenty-one billion, six hundred eighty-three million, twenty-one thousand, three hundred sixty-one".