66957087961 has 4 divisors (see below), whose sum is σ = 70895740212. Its totient is φ = 63018435712.

The previous prime is 66957087947. The next prime is 66957087973. The reversal of 66957087961 is 16978075966.

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 54403230025 + 12553857936 = 233245^2 + 112044^2 .

It is a cyclic number.

It is not a de Polignac number, because 66957087961 - 2⁷ = 66957087833 is a prime.

It is a super-2 number, since 2×66957087961² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66957087893 and 66957087902.

It is not an unprimeable number, because it can be changed into a prime (66957087061) 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, 1969326100 + ... + 1969326133.

It is an arithmetic number, because the mean of its divisors is an integer number (17723935053).

Almost surely, 2^66957087961 is an apocalyptic number.

It is an amenable number.

66957087961 is a deficient number, since it is larger than the sum of its proper divisors (3938652251).

66957087961 is a wasteful number, since it uses less digits than its factorization.

66957087961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3938652250.

The product of its (nonzero) digits is 34292160, while the sum is 64.

The spelling of 66957087961 in words is "sixty-six billion, nine hundred fifty-seven million, eighty-seven thousand, nine hundred sixty-one".