637666434421 has 2 divisors, whose sum is σ = 637666434422. Its totient is φ = 637666434420.

The previous prime is 637666434401. The next prime is 637666434439. The reversal of 637666434421 is 124434666736.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 618717535396 + 18948899025 = 786586^2 + 137655^2 .

It is a cyclic number.

It is not a de Polignac number, because 637666434421 - 2¹⁷ = 637666303349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (637666434401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 318833217210 + 318833217211.

It is an arithmetic number, because the mean of its divisors is an integer number (318833217211).

Almost surely, 2^637666434421 is an apocalyptic number.

It is an amenable number.

637666434421 is a deficient number, since it is larger than the sum of its proper divisors (1).

637666434421 is an equidigital number, since it uses as much as digits as its factorization.

637666434421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 10450944, while the sum is 52.

The spelling of 637666434421 in words is "six hundred thirty-seven billion, six hundred sixty-six million, four hundred thirty-four thousand, four hundred twenty-one".