261028657 has 8 divisors (see below), whose sum is σ = 266253480. Its totient is φ = 255815040.

The previous prime is 261028643. The next prime is 261028667. The reversal of 261028657 is 756820162.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 3779136 + 257249521 = 1944^2 + 16039^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 261028657 - 2⁷ = 261028529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261028667) 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, 56557 + ... + 60997.

It is an arithmetic number, because the mean of its divisors is an integer number (33281685).

Almost surely, 2^261028657 is an apocalyptic number.

It is an amenable number.

261028657 is a deficient number, since it is larger than the sum of its proper divisors (5224823).

261028657 is a wasteful number, since it uses less digits than its factorization.

261028657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5603.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 261028657 is about 16156.3813089442. The cubic root of 261028657 is about 639.0910412071.

The spelling of 261028657 in words is "two hundred sixty-one million, twenty-eight thousand, six hundred fifty-seven".