665615025 has 36 divisors (see below), whose sum is σ = 1262326572. Its totient is φ = 334110720.

The previous prime is 665615023. The next prime is 665615057. The reversal of 665615025 is 520516566.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 67519089 + 598095936 = 8217^2 + 24456^2 .

It is not a de Polignac number, because 665615025 - 2¹ = 665615023 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (665615023) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 83184 + ... + 90833.

It is an arithmetic number, because the mean of its divisors is an integer number (35064627).

Almost surely, 2^665615025 is an apocalyptic number.

It is an amenable number.

665615025 is a deficient number, since it is larger than the sum of its proper divisors (596711547).

665615025 is a wasteful number, since it uses less digits than its factorization.

665615025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 174050 (or 174042 counting only the distinct ones).

The product of its (nonzero) digits is 54000, while the sum is 36.

The square root of 665615025 is about 25799.5159838319. The cubic root of 665615025 is about 873.1208761823.

The spelling of 665615025 in words is "six hundred sixty-five million, six hundred fifteen thousand, twenty-five".