667216377721 has 32 divisors (see below), whose sum is σ = 765869322240. Its totient is φ = 577990473984.

The previous prime is 667216377691. The next prime is 667216377769. The reversal of 667216377721 is 127773612766.

It is not a de Polignac number, because 667216377721 - 2¹¹ = 667216375673 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (667216377781) 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, 505441 + ... + 1260913.

It is an arithmetic number, because the mean of its divisors is an integer number (23933416320).

Almost surely, 2^667216377721 is an apocalyptic number.

It is an amenable number.

667216377721 is a deficient number, since it is larger than the sum of its proper divisors (98652944519).

667216377721 is a wasteful number, since it uses less digits than its factorization.

667216377721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 755605.

The product of its digits is 6223392, while the sum is 55.

The spelling of 667216377721 in words is "six hundred sixty-seven billion, two hundred sixteen million, three hundred seventy-seven thousand, seven hundred twenty-one".