666522501 has 4 divisors (see below), whose sum is σ = 888696672. Its totient is φ = 444348332.

The previous prime is 666522433. The next prime is 666522503. The reversal of 666522501 is 105225666.

It is a happy number.

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 666522501 - 2²³ = 658133893 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666522503) 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, 111087081 + ... + 111087086.

It is an arithmetic number, because the mean of its divisors is an integer number (222174168).

Almost surely, 2^666522501 is an apocalyptic number.

It is an amenable number.

666522501 is a deficient number, since it is larger than the sum of its proper divisors (222174171).

666522501 is a wasteful number, since it uses less digits than its factorization.

666522501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 222174170.

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 666522501 is about 25817.0970676410. The cubic root of 666522501 is about 873.5174900416.

The spelling of 666522501 in words is "six hundred sixty-six million, five hundred twenty-two thousand, five hundred one".