66661038405 has 48 divisors (see below), whose sum is σ = 124662021120. Its totient is φ = 32757588864.

The previous prime is 66661038397. The next prime is 66661038421. The reversal of 66661038405 is 50483016666.

It is not a de Polignac number, because 66661038405 - 2³ = 66661038397 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 215836 + ... + 424154.

It is an arithmetic number, because the mean of its divisors is an integer number (2597125440).

Almost surely, 2^66661038405 is an apocalyptic number.

66661038405 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

66661038405 is a deficient number, since it is larger than the sum of its proper divisors (58000982715).

66661038405 is a wasteful number, since it uses less digits than its factorization.

66661038405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 208890 (or 208887 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The spelling of 66661038405 in words is "sixty-six billion, six hundred sixty-one million, thirty-eight thousand, four hundred five".