261657607 has 8 divisors (see below), whose sum is σ = 276035760. Its totient is φ = 247340160.

The previous prime is 261657593. The next prime is 261657619. The reversal of 261657607 is 706756162.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261657607 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261657607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261657677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6178 + ... + 23695.

It is an arithmetic number, because the mean of its divisors is an integer number (34504470).

Almost surely, 2^261657607 is an apocalyptic number.

261657607 is a deficient number, since it is larger than the sum of its proper divisors (14378153).

261657607 is a wasteful number, since it uses less digits than its factorization.

261657607 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30353.

The product of its (nonzero) digits is 105840, while the sum is 40.

The square root of 261657607 is about 16175.8340434118. The cubic root of 261657607 is about 639.6039272989.

The spelling of 261657607 in words is "two hundred sixty-one million, six hundred fifty-seven thousand, six hundred seven".