661725441 has 24 divisors (see below), whose sum is σ = 1030684200. Its totient is φ = 406688256.

The previous prime is 661725439. The next prime is 661725487. The reversal of 661725441 is 144527166.

It can be written as a sum of positive squares in 4 ways, for example, as 269091216 + 392634225 = 16404^2 + 19815^2 .

It is not a de Polignac number, because 661725441 - 2¹ = 661725439 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 661725396 and 661725405.

It is not an unprimeable number, because it can be changed into a prime (661725431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 99385 + ... + 105833.

It is an arithmetic number, because the mean of its divisors is an integer number (42945175).

Almost surely, 2^661725441 is an apocalyptic number.

It is an amenable number.

661725441 is a deficient number, since it is larger than the sum of its proper divisors (368958759).

661725441 is a wasteful number, since it uses less digits than its factorization.

661725441 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7345 (or 7342 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 661725441 is about 25724.0245879217. The cubic root of 661725441 is about 871.4168312914.

The spelling of 661725441 in words is "six hundred sixty-one million, seven hundred twenty-five thousand, four hundred forty-one".