661909125 has 32 divisors (see below), whose sum is σ = 1128306816. Its totient is φ = 344400000.

The previous prime is 661909123. The next prime is 661909153. The reversal of 661909125 is 521909166.

It is not a de Polignac number, because 661909125 - 2¹ = 661909123 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661909123) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6151 + ... + 36900.

It is an arithmetic number, because the mean of its divisors is an integer number (35259588).

Almost surely, 2^661909125 is an apocalyptic number.

It is an amenable number.

661909125 is a deficient number, since it is larger than the sum of its proper divisors (466397691).

661909125 is a wasteful number, since it uses less digits than its factorization.

661909125 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43110 (or 43100 counting only the distinct ones).

The product of its (nonzero) digits is 29160, while the sum is 39.

The square root of 661909125 is about 25727.5946213399. The cubic root of 661909125 is about 871.4974541153.

The spelling of 661909125 in words is "six hundred sixty-one million, nine hundred nine thousand, one hundred twenty-five".