66949616740681 has 4 divisors (see below), whose sum is σ = 69109281796864. Its totient is φ = 64789951684500.

The previous prime is 66949616740679. The next prime is 66949616740759. The reversal of 66949616740681 is 18604761694966.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 66949616740681 - 2¹ = 66949616740679 is a prime.

It is a super-2 number, since 2×66949616740681² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66949616740631) 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, 1079832528045 + ... + 1079832528106.

It is an arithmetic number, because the mean of its divisors is an integer number (17277320449216).

Almost surely, 2^{66949616740681} is an apocalyptic number.

It is an amenable number.

66949616740681 is a deficient number, since it is larger than the sum of its proper divisors (2159665056183).

66949616740681 is a wasteful number, since it uses less digits than its factorization.

66949616740681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2159665056182.

The product of its (nonzero) digits is 564350976, while the sum is 73.

The spelling of 66949616740681 in words is "sixty-six trillion, nine hundred forty-nine billion, six hundred sixteen million, seven hundred forty thousand, six hundred eighty-one".