660640225 has 48 divisors (see below), whose sum is σ = 987365376. Its totient is φ = 428904000.

The previous prime is 660640219. The next prime is 660640229. The reversal of 660640225 is 522046066.

It is not a de Polignac number, because 660640225 - 2²⁹ = 123769313 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31).

It is not an unprimeable number, because it can be changed into a prime (660640229) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 253680 + ... + 256270.

It is an arithmetic number, because the mean of its divisors is an integer number (20570112).

Almost surely, 2^660640225 is an apocalyptic number.

It is an amenable number.

660640225 is a deficient number, since it is larger than the sum of its proper divisors (326725151).

660640225 is a wasteful number, since it uses less digits than its factorization.

660640225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2686 (or 2681 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 31.

The square root of 660640225 is about 25702.9224992023. The cubic root of 660640225 is about 870.9402021319.

The spelling of 660640225 in words is "six hundred sixty million, six hundred forty thousand, two hundred twenty-five".