66375695421 has 30 divisors (see below), whose sum is σ = 111848719710. Its totient is φ = 37928956464.

The previous prime is 66375695387. The next prime is 66375695437. The reversal of 66375695421 is 12459657366.

66375695421 is a `hidden beast` number, since 6 + 6 + 3 + 7 + 569 + 54 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 46377776025 + 19997919396 = 215355^2 + 141414^2 .

It is not a de Polignac number, because 66375695421 - 2¹⁴ = 66375679037 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66375695461) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 1514226 + ... + 1557443.

It is an arithmetic number, because the mean of its divisors is an integer number (3728290657).

Almost surely, 2^66375695421 is an apocalyptic number.

It is an amenable number.

66375695421 is a deficient number, since it is larger than the sum of its proper divisors (45473024289).

66375695421 is an equidigital number, since it uses as much as digits as its factorization.

66375695421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3071703 (or 3071679 counting only the distinct ones).

The product of its digits is 8164800, while the sum is 54.

The spelling of 66375695421 in words is "sixty-six billion, three hundred seventy-five million, six hundred ninety-five thousand, four hundred twenty-one".