163666764421 has 2 divisors, whose sum is σ = 163666764422. Its totient is φ = 163666764420.

The previous prime is 163666764419. The next prime is 163666764431. The reversal of 163666764421 is 124467666361.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 137125793025 + 26540971396 = 370305^2 + 162914^2 .

It is a cyclic number.

It is not a de Polignac number, because 163666764421 - 2¹ = 163666764419 is a prime.

It is a super-2 number, since 2×163666764421² (a number of 23 digits) contains 22 as substring.

Together with 163666764419, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (163666764431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 81833382210 + 81833382211.

It is an arithmetic number, because the mean of its divisors is an integer number (81833382211).

Almost surely, 2^163666764421 is an apocalyptic number.

It is an amenable number.

163666764421 is a deficient number, since it is larger than the sum of its proper divisors (1).

163666764421 is an equidigital number, since it uses as much as digits as its factorization.

163666764421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5225472, while the sum is 52.

The spelling of 163666764421 in words is "one hundred sixty-three billion, six hundred sixty-six million, seven hundred sixty-four thousand, four hundred twenty-one".