261619 has 2 divisors, whose sum is σ = 261620. Its totient is φ = 261618.

The previous prime is 261601. The next prime is 261631. The reversal of 261619 is 916162.

261619 is nontrivially palindromic in base 16.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 261619 - 2⁵ = 261587 is a prime.

It is a super-2 number, since 2×261619² = 136889002322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 261593 and 261602.

It is not a weakly prime, because it can be changed into another prime (264619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130809 + 130810.

It is an arithmetic number, because the mean of its divisors is an integer number (130810).

2²⁶¹⁶¹⁹ is an apocalyptic number.

261619 is a deficient number, since it is larger than the sum of its proper divisors (1).

261619 is an equidigital number, since it uses as much as digits as its factorization.

261619 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 25.

The square root of 261619 is about 511.4870477343. The cubic root of 261619 is about 63.9572468371.

The spelling of 261619 in words is "two hundred sixty-one thousand, six hundred nineteen".