66681020203 has 6 divisors (see below), whose sum is σ = 77567717436. Its totient is φ = 57155160132.

The previous prime is 66681020183. The next prime is 66681020249. The reversal of 66681020203 is 30202018666.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-66681020203 is a prime.

It is a super-2 number, since 2×66681020203² (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 (66681020803) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 680418525 + ... + 680418622.

It is an arithmetic number, because the mean of its divisors is an integer number (12927952906).

Almost surely, 2^66681020203 is an apocalyptic number.

66681020203 is a deficient number, since it is larger than the sum of its proper divisors (10886697233).

66681020203 is a wasteful number, since it uses less digits than its factorization.

66681020203 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1360837161 (or 1360837154 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 34.

Adding to 66681020203 its reverse (30202018666), we get a palindrome (96883038869).

The spelling of 66681020203 in words is "sixty-six billion, six hundred eighty-one million, twenty thousand, two hundred three".