66900639173 has 2 divisors, whose sum is σ = 66900639174. Its totient is φ = 66900639172.

The previous prime is 66900639137. The next prime is 66900639191. The reversal of 66900639173 is 37193600966.

It is a happy number.

Together with previous prime (66900639137) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57800814724 + 9099824449 = 240418^2 + 95393^2 .

It is a cyclic number.

It is not a de Polignac number, because 66900639173 - 2⁶ = 66900639109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66900639193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33450319586 + 33450319587.

It is an arithmetic number, because the mean of its divisors is an integer number (33450319587).

Almost surely, 2^66900639173 is an apocalyptic number.

It is an amenable number.

66900639173 is a deficient number, since it is larger than the sum of its proper divisors (1).

66900639173 is an equidigital number, since it uses as much as digits as its factorization.

66900639173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1102248, while the sum is 50.

The spelling of 66900639173 in words is "sixty-six billion, nine hundred million, six hundred thirty-nine thousand, one hundred seventy-three".