261220657 has 8 divisors (see below), whose sum is σ = 283019616. Its totient is φ = 240136512.

The previous prime is 261220627. The next prime is 261220693. The reversal of 261220657 is 756022162.

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-261220657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261220627) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 177943 + ... + 179404.

It is an arithmetic number, because the mean of its divisors is an integer number (35377452).

Almost surely, 2^261220657 is an apocalyptic number.

It is an amenable number.

261220657 is a deficient number, since it is larger than the sum of its proper divisors (21798959).

261220657 is a wasteful number, since it uses less digits than its factorization.

261220657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 357407.

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 261220657 is about 16162.3221413261. The cubic root of 261220657 is about 639.2476975786.

The spelling of 261220657 in words is "two hundred sixty-one million, two hundred twenty thousand, six hundred fifty-seven".