261370657 has 2 divisors, whose sum is σ = 261370658. Its totient is φ = 261370656.

The previous prime is 261370651. The next prime is 261370673. The reversal of 261370657 is 756073162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 259564321 + 1806336 = 16111^2 + 1344^2 .

It is a cyclic number.

It is not a de Polignac number, because 261370657 - 2¹¹ = 261368609 is a prime.

It is a super-2 number, since 2×261370657² = 136629240681223298, which contains 22 as substring.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (261370651) 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 as a sum of consecutive naturals, namely, 130685328 + 130685329.

It is an arithmetic number, because the mean of its divisors is an integer number (130685329).

Almost surely, 2^261370657 is an apocalyptic number.

It is an amenable number.

261370657 is a deficient number, since it is larger than the sum of its proper divisors (1).

261370657 is an equidigital number, since it uses as much as digits as its factorization.

261370657 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 52920, while the sum is 37.

The square root of 261370657 is about 16166.9618976479. The cubic root of 261370657 is about 639.3700319656.

The spelling of 261370657 in words is "two hundred sixty-one million, three hundred seventy thousand, six hundred fifty-seven".