667719121 has 2 divisors, whose sum is σ = 667719122. Its totient is φ = 667719120.

The previous prime is 667719103. The next prime is 667719127. The reversal of 667719121 is 121917766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 455609025 + 212110096 = 21345^2 + 14564^2 .

It is a cyclic number.

It is not a de Polignac number, because 667719121 - 2²⁷ = 533501393 is a prime.

It is not a weakly prime, because it can be changed into another prime (667719127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333859560 + 333859561.

It is an arithmetic number, because the mean of its divisors is an integer number (333859561).

Almost surely, 2^667719121 is an apocalyptic number.

It is an amenable number.

667719121 is a deficient number, since it is larger than the sum of its proper divisors (1).

667719121 is an equidigital number, since it uses as much as digits as its factorization.

667719121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 31752, while the sum is 40.

The square root of 667719121 is about 25840.2616279325. The cubic root of 667719121 is about 874.0399248135.

The spelling of 667719121 in words is "six hundred sixty-seven million, seven hundred nineteen thousand, one hundred twenty-one".