667728577 has 4 divisors (see below), whose sum is σ = 681935616. Its totient is φ = 653521540.

The previous prime is 667728569. The next prime is 667728599. The reversal of 667728577 is 775827766.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 667728577 - 2³ = 667728569 is a prime.

It is a super-2 number, since 2×667728577² = 891722905084889858, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (667728557) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7103449 + ... + 7103542.

It is an arithmetic number, because the mean of its divisors is an integer number (170483904).

Almost surely, 2^667728577 is an apocalyptic number.

It is an amenable number.

667728577 is a deficient number, since it is larger than the sum of its proper divisors (14207039).

667728577 is a wasteful number, since it uses less digits than its factorization.

667728577 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14207038.

The product of its digits is 6914880, while the sum is 55.

The square root of 667728577 is about 25840.4445975684. Note that the first 3 decimals coincide. The cubic root of 667728577 is about 874.0440507412.

The spelling of 667728577 in words is "six hundred sixty-seven million, seven hundred twenty-eight thousand, five hundred seventy-seven".