21561205711067 has 8 divisors (see below), whose sum is σ = 23852601453312. Its totient is φ = 19325024324200.

The previous prime is 21561205711057. The next prime is 21561205711193. The reversal of 21561205711067 is 76011750216512.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21561205711067 - 2¹⁴ = 21561205694683 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21561205711037) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13803588023 + ... + 13803589584.

It is an arithmetic number, because the mean of its divisors is an integer number (2981575181664).

Almost surely, 2^{21561205711067} is an apocalyptic number.

21561205711067 is a deficient number, since it is larger than the sum of its proper divisors (2291395742245).

21561205711067 is a wasteful number, since it uses less digits than its factorization.

21561205711067 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27607177689.

The product of its (nonzero) digits is 176400, while the sum is 44.

Adding to 21561205711067 its reverse (76011750216512), we get a palindrome (97572955927579).

Subtracting 21561205711067 from its reverse (76011750216512), we obtain a palindrome (54450544505445).

The spelling of 21561205711067 in words is "twenty-one trillion, five hundred sixty-one billion, two hundred five million, seven hundred eleven thousand, sixty-seven".