261321201 has 32 divisors (see below), whose sum is σ = 395041920. Its totient is φ = 170698752.

The previous prime is 261321187. The next prime is 261321209. The reversal of 261321201 is 102123162.

It is not a de Polignac number, because 261321201 - 2¹³ = 261313009 is a prime.

It is not an unprimeable number, because it can be changed into a prime (261321209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 295506 + ... + 296388.

It is an arithmetic number, because the mean of its divisors is an integer number (12345060).

Almost surely, 2^261321201 is an apocalyptic number.

It is an amenable number.

261321201 is a deficient number, since it is larger than the sum of its proper divisors (133720719).

261321201 is a wasteful number, since it uses less digits than its factorization.

261321201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1102 (or 1096 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

The square root of 261321201 is about 16165.4322862087. The cubic root of 261321201 is about 639.3297026758.

Adding to 261321201 its reverse (102123162), we get a palindrome (363444363).

The spelling of 261321201 in words is "two hundred sixty-one million, three hundred twenty-one thousand, two hundred one".