667625981 has 8 divisors (see below), whose sum is σ = 735002400. Its totient is φ = 601363440.

The previous prime is 667625963. The next prime is 667626017. The reversal of 667625981 is 189526766.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 667625981 - 2¹⁰ = 667624957 is a prime.

It is a super-2 number, since 2×667625981² = 891448901012424722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (667625941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 277211 + ... + 279608.

It is an arithmetic number, because the mean of its divisors is an integer number (91875300).

Almost surely, 2^667625981 is an apocalyptic number.

It is an amenable number.

667625981 is a deficient number, since it is larger than the sum of its proper divisors (67376419).

667625981 is a wasteful number, since it uses less digits than its factorization.

667625981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 556939.

The product of its digits is 1088640, while the sum is 50.

The square root of 667625981 is about 25838.4593387454. The cubic root of 667625981 is about 873.9992830419. Note that the first 3 decimals are identical.

The spelling of 667625981 in words is "six hundred sixty-seven million, six hundred twenty-five thousand, nine hundred eighty-one".