661489375 has 10 divisors (see below), whose sum is σ = 826597904. Its totient is φ = 529191000.

The previous prime is 661489373. The next prime is 661489393. The reversal of 661489375 is 573984166.

It is not a de Polignac number, because 661489375 - 2¹ = 661489373 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661489373) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 528567 + ... + 529816.

Almost surely, 2^661489375 is an apocalyptic number.

661489375 is a deficient number, since it is larger than the sum of its proper divisors (165108529).

661489375 is an equidigital number, since it uses as much as digits as its factorization.

661489375 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1058403 (or 1058388 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 49.

The square root of 661489375 is about 25719.4357441994. The cubic root of 661489375 is about 871.3131949795.

The spelling of 661489375 in words is "six hundred sixty-one million, four hundred eighty-nine thousand, three hundred seventy-five".