261629 has 4 divisors (see below), whose sum is σ = 265980. Its totient is φ = 257280.

The previous prime is 261619. The next prime is 261631. The reversal of 261629 is 926162.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 122500 + 139129 = 350^2 + 373^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261629 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 261598 and 261607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261619) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2084 + ... + 2205.

It is an arithmetic number, because the mean of its divisors is an integer number (66495).

2²⁶¹⁶²⁹ is an apocalyptic number.

It is an amenable number.

261629 is a deficient number, since it is larger than the sum of its proper divisors (4351).

261629 is an equidigital number, since it uses as much as digits as its factorization.

261629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4350.

The product of its digits is 1296, while the sum is 26.

The square root of 261629 is about 511.4968230595. The cubic root of 261629 is about 63.9580617172.

The spelling of 261629 in words is "two hundred sixty-one thousand, six hundred twenty-nine".