667631 has 2 divisors, whose sum is σ = 667632. Its totient is φ = 667630.

The previous prime is 667577. The next prime is 667643. The reversal of 667631 is 136766.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 667631 - 2¹⁰ = 666607 is a prime.

It is a super-2 number, since 2×667631² = 891462304322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 667594 and 667603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (667691) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 333815 + 333816.

It is an arithmetic number, because the mean of its divisors is an integer number (333816).

2⁶⁶⁷⁶³¹ is an apocalyptic number.

667631 is a deficient number, since it is larger than the sum of its proper divisors (1).

667631 is an equidigital number, since it uses as much as digits as its factorization.

667631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4536, while the sum is 29.

The square root of 667631 is about 817.0868986834. The cubic root of 667631 is about 87.4001473186.

The spelling of 667631 in words is "six hundred sixty-seven thousand, six hundred thirty-one".