261938 has 4 divisors (see below), whose sum is σ = 392910. Its totient is φ = 130968.

The previous prime is 261917. The next prime is 261959. The reversal of 261938 is 839162.

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

It is an interprime number because it is at equal distance from previous prime (261917) and next prime (261959).

It can be written as a sum of positive squares in only one way, i.e., 157609 + 104329 = 397^2 + 323^2 .

It is a super-2 number, since 2×261938² = 137223031688, which contains 22 as substring.

It is an Ulam number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 261938.

It is an unprimeable number.

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, 65483 + ... + 65486.

261938 is a Friedman number, since it can be written as 8^6-23*9+1, using all its digits and the basic arithmetic operations.

2²⁶¹⁹³⁸ is an apocalyptic number.

261938 is a deficient number, since it is larger than the sum of its proper divisors (130972).

261938 is a wasteful number, since it uses less digits than its factorization.

261938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130971.

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

The square root of 261938 is about 511.7987885879. The cubic root of 261938 is about 63.9832312839.

The spelling of 261938 in words is "two hundred sixty-one thousand, nine hundred thirty-eight".