661609395 has 48 divisors (see below), whose sum is σ = 1205304672. Its totient is φ = 335301120.

The previous prime is 661609387. The next prime is 661609397. The reversal of 661609395 is 593906166.

661609395 is a `hidden beast` number, since 6 + 6 + 1 + 609 + 39 + 5 = 666.

It is not a de Polignac number, because 661609395 - 2³ = 661609387 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 661609395.

It is not an unprimeable number, because it can be changed into a prime (661609397) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 66975 + ... + 76215.

It is an arithmetic number, because the mean of its divisors is an integer number (25110514).

Almost surely, 2^661609395 is an apocalyptic number.

661609395 is a deficient number, since it is larger than the sum of its proper divisors (543695277).

661609395 is a wasteful number, since it uses less digits than its factorization.

661609395 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9332 (or 9329 counting only the distinct ones).

The product of its (nonzero) digits is 262440, while the sum is 45.

The square root of 661609395 is about 25721.7688932935. The cubic root of 661609395 is about 871.3658885372.

The spelling of 661609395 in words is "six hundred sixty-one million, six hundred nine thousand, three hundred ninety-five".