66646069281 has 27 divisors (see below), whose sum is σ = 105827167537. Its totient is φ = 40386393960.

The previous prime is 66646069267. The next prime is 66646069331. The reversal of 66646069281 is 18296064666.

The square root of 66646069281 is 258159.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 66646069281 - 2¹¹ = 66646067233 is a prime.

It is a super-2 number, since 2×66646069281² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66646069081) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 8515336 + ... + 8523158.

Almost surely, 2^66646069281 is an apocalyptic number.

66646069281 is the 258159-th square number.

66646069281 is the 129080-th centered octagonal number.

It is an amenable number.

66646069281 is a deficient number, since it is larger than the sum of its proper divisors (39181098256).

66646069281 is an frugal number, since it uses more digits than its factorization.

66646069281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15674 (or 7837 counting only the distinct ones).

The product of its (nonzero) digits is 4478976, while the sum is 54.

The spelling of 66646069281 in words is "sixty-six billion, six hundred forty-six million, sixty-nine thousand, two hundred eighty-one".