21669315934421 has 2 divisors, whose sum is σ = 21669315934422. Its totient is φ = 21669315934420.

The previous prime is 21669315934381. The next prime is 21669315934463. The reversal of 21669315934421 is 12443951396612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21358354680100 + 310961254321 = 4621510^2 + 557639^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21669315934421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21669315934121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10834657967210 + 10834657967211.

It is an arithmetic number, because the mean of its divisors is an integer number (10834657967211).

Almost surely, 2^{21669315934421} is an apocalyptic number.

It is an amenable number.

21669315934421 is a deficient number, since it is larger than the sum of its proper divisors (1).

21669315934421 is an equidigital number, since it uses as much as digits as its factorization.

21669315934421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8398080, while the sum is 56.

The spelling of 21669315934421 in words is "twenty-one trillion, six hundred sixty-nine billion, three hundred fifteen million, nine hundred thirty-four thousand, four hundred twenty-one".