667728457 has 12 divisors (see below), whose sum is σ = 772581040. Its totient is φ = 575075160.

The previous prime is 667728409. The next prime is 667728491. The reversal of 667728457 is 754827766.

It is a de Polignac number, because none of the positive numbers 2^k-667728457 is a prime.

It is a super-2 number, since 2×667728457² = 891722584575201698, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (667728407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 142923 + ... + 147520.

Almost surely, 2^667728457 is an apocalyptic number.

It is an amenable number.

667728457 is a deficient number, since it is larger than the sum of its proper divisors (104852583).

667728457 is a wasteful number, since it uses less digits than its factorization.

667728457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290484 (or 290473 counting only the distinct ones).

The product of its digits is 3951360, while the sum is 52.

The square root of 667728457 is about 25840.4422756268. The cubic root of 667728457 is about 874.0439983820.

The spelling of 667728457 in words is "six hundred sixty-seven million, seven hundred twenty-eight thousand, four hundred fifty-seven".