221943891517 has 2 divisors, whose sum is σ = 221943891518. Its totient is φ = 221943891516.

The previous prime is 221943891509. The next prime is 221943891551. The reversal of 221943891517 is 715198349122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207955152441 + 13988739076 = 456021^2 + 118274^2 .

It is a cyclic number.

It is not a de Polignac number, because 221943891517 - 2³ = 221943891509 is a prime.

It is a super-2 number, since 2×221943891517² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221943891317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110971945758 + 110971945759.

It is an arithmetic number, because the mean of its divisors is an integer number (110971945759).

Almost surely, 2^221943891517 is an apocalyptic number.

It is an amenable number.

221943891517 is a deficient number, since it is larger than the sum of its proper divisors (1).

221943891517 is an equidigital number, since it uses as much as digits as its factorization.

221943891517 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 52.

The spelling of 221943891517 in words is "two hundred twenty-one billion, nine hundred forty-three million, eight hundred ninety-one thousand, five hundred seventeen".