667231536421 has 2 divisors, whose sum is σ = 667231536422. Its totient is φ = 667231536420.

The previous prime is 667231536403. The next prime is 667231536427. The reversal of 667231536421 is 124635132766.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 647680505796 + 19551030625 = 804786^2 + 139825^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-667231536421 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667231536427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333615768210 + 333615768211.

It is an arithmetic number, because the mean of its divisors is an integer number (333615768211).

Almost surely, 2^667231536421 is an apocalyptic number.

It is an amenable number.

667231536421 is a deficient number, since it is larger than the sum of its proper divisors (1).

667231536421 is an equidigital number, since it uses as much as digits as its factorization.

667231536421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1088640, while the sum is 46.

The spelling of 667231536421 in words is "six hundred sixty-seven billion, two hundred thirty-one million, five hundred thirty-six thousand, four hundred twenty-one".