667723365561 has 32 divisors (see below), whose sum is σ = 1095595130880. Its totient is φ = 353025075456.

The previous prime is 667723365467. The next prime is 667723365581. The reversal of 667723365561 is 165563327766.

It is not a de Polignac number, because 667723365561 - 2¹¹ = 667723363513 is a prime.

It is a super-2 number, since 2×667723365561² (a number of 24 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (57) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (667723365581) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 15829561 + ... + 15871686.

It is an arithmetic number, because the mean of its divisors is an integer number (34237347840).

Almost surely, 2^667723365561 is an apocalyptic number.

It is an amenable number.

667723365561 is a deficient number, since it is larger than the sum of its proper divisors (427871765319).

667723365561 is a wasteful number, since it uses less digits than its factorization.

667723365561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31701333.

The product of its digits is 28576800, while the sum is 57.

The spelling of 667723365561 in words is "six hundred sixty-seven billion, seven hundred twenty-three million, three hundred sixty-five thousand, five hundred sixty-one".