21621273216149 has 2 divisors, whose sum is σ = 21621273216150. Its totient is φ = 21621273216148.

The previous prime is 21621273216121. The next prime is 21621273216157. The reversal of 21621273216149 is 94161237212612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17870783938225 + 3750489277924 = 4227385^2 + 1936618^2 .

It is a cyclic number.

It is not a de Polignac number, because 21621273216149 - 2⁴⁰ = 20521761588373 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21621273216649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10810636608074 + 10810636608075.

It is an arithmetic number, because the mean of its divisors is an integer number (10810636608075).

Almost surely, 2^{21621273216149} is an apocalyptic number.

It is an amenable number.

21621273216149 is a deficient number, since it is larger than the sum of its proper divisors (1).

21621273216149 is an equidigital number, since it uses as much as digits as its factorization.

21621273216149 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 47.

The spelling of 21621273216149 in words is "twenty-one trillion, six hundred twenty-one billion, two hundred seventy-three million, two hundred sixteen thousand, one hundred forty-nine".