21168416837 has 2 divisors, whose sum is σ = 21168416838. Its totient is φ = 21168416836.

The previous prime is 21168416833. The next prime is 21168416869. The reversal of 21168416837 is 73861486112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16187727361 + 4980689476 = 127231^2 + 70574^2 .

It is a cyclic number.

It is not a de Polignac number, because 21168416837 - 2² = 21168416833 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21168416791 and 21168416800.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21168416833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10584208418 + 10584208419.

It is an arithmetic number, because the mean of its divisors is an integer number (10584208419).

Almost surely, 2^21168416837 is an apocalyptic number.

It is an amenable number.

21168416837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21168416837 is an equidigital number, since it uses as much as digits as its factorization.

21168416837 is an evil number, because the sum of its binary digits is even.

The product of its digits is 387072, while the sum is 47.

The spelling of 21168416837 in words is "twenty-one billion, one hundred sixty-eight million, four hundred sixteen thousand, eight hundred thirty-seven".