661244525 has 6 divisors (see below), whose sum is σ = 819943242. Its totient is φ = 528995600.

The previous prime is 661244509. The next prime is 661244531. The reversal of 661244525 is 525442166.

It can be written as a sum of positive squares in 3 ways, for example, as 18267076 + 642977449 = 4274^2 + 25357^2 .

It is not a de Polignac number, because 661244525 - 2⁴ = 661244509 is a prime.

It is a Duffinian number.

It is a congruent 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 5 ways as a sum of consecutive naturals, for example, 13224866 + ... + 13224915.

It is an arithmetic number, because the mean of its divisors is an integer number (136657207).

Almost surely, 2^661244525 is an apocalyptic number.

It is an amenable number.

661244525 is a deficient number, since it is larger than the sum of its proper divisors (158698717).

661244525 is a wasteful number, since it uses less digits than its factorization.

661244525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26449791 (or 26449786 counting only the distinct ones).

The product of its digits is 57600, while the sum is 35.

The square root of 661244525 is about 25714.6752847474. The cubic root of 661244525 is about 871.2056763143.

The spelling of 661244525 in words is "six hundred sixty-one million, two hundred forty-four thousand, five hundred twenty-five".