261930397 has 4 divisors (see below), whose sum is σ = 262189980. Its totient is φ = 261670816.

The previous prime is 261930359. The next prime is 261930413. The reversal of 261930397 is 793039162.

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 18757561 + 243172836 = 4331^2 + 15594^2 .

It is a cyclic number.

It is not a de Polignac number, because 261930397 - 2¹¹ = 261928349 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261930797) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128272 + ... + 130297.

It is an arithmetic number, because the mean of its divisors is an integer number (65547495).

Almost surely, 2^261930397 is an apocalyptic number.

It is an amenable number.

261930397 is a deficient number, since it is larger than the sum of its proper divisors (259583).

261930397 is a wasteful number, since it uses less digits than its factorization.

261930397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259582.

The product of its (nonzero) digits is 61236, while the sum is 40.

The square root of 261930397 is about 16184.2638695740. The cubic root of 261930397 is about 639.8261221980.

The spelling of 261930397 in words is "two hundred sixty-one million, nine hundred thirty thousand, three hundred ninety-seven".