66746042921 has 4 divisors (see below), whose sum is σ = 67131858372. Its totient is φ = 66360227472.

The previous prime is 66746042899. The next prime is 66746042933. The reversal of 66746042921 is 12924064766.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 64079353321 + 2666689600 = 253139^2 + 51640^2 .

It is a cyclic number.

It is not a de Polignac number, because 66746042921 - 2²² = 66741848617 is a prime.

It is a super-2 number, since 2×66746042921² (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 (66746042221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 192907466 + ... + 192907811.

It is an arithmetic number, because the mean of its divisors is an integer number (16782964593).

Almost surely, 2^66746042921 is an apocalyptic number.

It is an amenable number.

66746042921 is a deficient number, since it is larger than the sum of its proper divisors (385815451).

66746042921 is a wasteful number, since it uses less digits than its factorization.

66746042921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385815450.

The product of its (nonzero) digits is 870912, while the sum is 47.

The spelling of 66746042921 in words is "sixty-six billion, seven hundred forty-six million, forty-two thousand, nine hundred twenty-one".