21166201447 has 2 divisors, whose sum is σ = 21166201448. Its totient is φ = 21166201446.

The previous prime is 21166201439. The next prime is 21166201487. The reversal of 21166201447 is 74410266112.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21166201447 - 2³ = 21166201439 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21166201487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10583100723 + 10583100724.

It is an arithmetic number, because the mean of its divisors is an integer number (10583100724).

Almost surely, 2^21166201447 is an apocalyptic number.

21166201447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21166201447 is an equidigital number, since it uses as much as digits as its factorization.

21166201447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 34.

Adding to 21166201447 its reverse (74410266112), we get a palindrome (95576467559).

The spelling of 21166201447 in words is "twenty-one billion, one hundred sixty-six million, two hundred one thousand, four hundred forty-seven".