661252506 has 16 divisors (see below), whose sum is σ = 1365166848. Its totient is φ = 213307200.

The previous prime is 661252483. The next prime is 661252517. The reversal of 661252506 is 605252166.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1777375 + ... + 1777746.

It is an arithmetic number, because the mean of its divisors is an integer number (85322928).

Almost surely, 2^661252506 is an apocalyptic number.

661252506 is an abundant number, since it is smaller than the sum of its proper divisors (703914342).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661252506 is a wasteful number, since it uses less digits than its factorization.

661252506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3555157.

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

The square root of 661252506 is about 25714.8304680393. The cubic root of 661252506 is about 871.2091813538.

The spelling of 661252506 in words is "six hundred sixty-one million, two hundred fifty-two thousand, five hundred six".