261389 has 2 divisors, whose sum is σ = 261390. Its totient is φ = 261388.

The previous prime is 261379. The next prime is 261407. The reversal of 261389 is 983162.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 133225 + 128164 = 365^2 + 358^2 .

It is a cyclic number.

It is not a de Polignac number, because 261389 - 2¹² = 257293 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (261329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130694 + 130695.

It is an arithmetic number, because the mean of its divisors is an integer number (130695).

2²⁶¹³⁸⁹ is an apocalyptic number.

It is an amenable number.

261389 is a deficient number, since it is larger than the sum of its proper divisors (1).

261389 is an equidigital number, since it uses as much as digits as its factorization.

261389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 29.

The square root of 261389 is about 511.2621636695. The cubic root of 261389 is about 63.9384988618.

The spelling of 261389 in words is "two hundred sixty-one thousand, three hundred eighty-nine".