261573121 has 2 divisors, whose sum is σ = 261573122. Its totient is φ = 261573120.

The previous prime is 261573107. The next prime is 261573131. The reversal of 261573121 is 121375162.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 259854400 + 1718721 = 16120^2 + 1311^2 .

It is a cyclic number.

It is not a de Polignac number, because 261573121 - 2¹³ = 261564929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261573121.

It is not a weakly prime, because it can be changed into another prime (261573131) by changing a digit.

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, 130786560 + 130786561.

It is an arithmetic number, because the mean of its divisors is an integer number (130786561).

Almost surely, 2^261573121 is an apocalyptic number.

It is an amenable number.

261573121 is a deficient number, since it is larger than the sum of its proper divisors (1).

261573121 is an equidigital number, since it uses as much as digits as its factorization.

261573121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2520, while the sum is 28.

The square root of 261573121 is about 16173.2223443567. Note that the first 3 decimals coincide. The cubic root of 261573121 is about 639.5350798267.

The spelling of 261573121 in words is "two hundred sixty-one million, five hundred seventy-three thousand, one hundred twenty-one".