667072421 has 2 divisors, whose sum is σ = 667072422. Its totient is φ = 667072420.

The previous prime is 667072361. The next prime is 667072429. The reversal of 667072421 is 124270766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 618268225 + 48804196 = 24865^2 + 6986^2 .

It is a cyclic number.

It is not a de Polignac number, because 667072421 - 2²⁶ = 599963557 is a prime.

It is a super-2 number, since 2×667072421² = 889971229717602482, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667072429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333536210 + 333536211.

It is an arithmetic number, because the mean of its divisors is an integer number (333536211).

Almost surely, 2^667072421 is an apocalyptic number.

It is an amenable number.

667072421 is a deficient number, since it is larger than the sum of its proper divisors (1).

667072421 is an equidigital number, since it uses as much as digits as its factorization.

667072421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28224, while the sum is 35.

The square root of 667072421 is about 25827.7451783929. The cubic root of 667072421 is about 873.7576583222.

The spelling of 667072421 in words is "six hundred sixty-seven million, seventy-two thousand, four hundred twenty-one".