221995012621 has 2 divisors, whose sum is σ = 221995012622. Its totient is φ = 221995012620.

The previous prime is 221995012597. The next prime is 221995012663. The reversal of 221995012621 is 126210599122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 139962033225 + 82032979396 = 374115^2 + 286414^2 .

It is a cyclic number.

It is not a de Polignac number, because 221995012621 - 2⁷ = 221995012493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221995012021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110997506310 + 110997506311.

It is an arithmetic number, because the mean of its divisors is an integer number (110997506311).

Almost surely, 2^221995012621 is an apocalyptic number.

It is an amenable number.

221995012621 is a deficient number, since it is larger than the sum of its proper divisors (1).

221995012621 is an equidigital number, since it uses as much as digits as its factorization.

221995012621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 38880, while the sum is 40.

The spelling of 221995012621 in words is "two hundred twenty-one billion, nine hundred ninety-five million, twelve thousand, six hundred twenty-one".