261655201 has 4 divisors (see below), whose sum is σ = 262697904. Its totient is φ = 260612500.

The previous prime is 261655193. The next prime is 261655237. The reversal of 261655201 is 102556162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 261655201 - 2³ = 261655193 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 261655201.

It is not an unprimeable number, because it can be changed into a prime (261655271) 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 in 3 ways as a sum of consecutive naturals, for example, 520975 + ... + 521476.

It is an arithmetic number, because the mean of its divisors is an integer number (65674476).

Almost surely, 2^261655201 is an apocalyptic number.

It is an amenable number.

261655201 is a deficient number, since it is larger than the sum of its proper divisors (1042703).

261655201 is a wasteful number, since it uses less digits than its factorization.

261655201 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1042702.

The product of its (nonzero) digits is 3600, while the sum is 28.

The square root of 261655201 is about 16175.7596730416. The cubic root of 261655201 is about 639.6019668593.

The spelling of 261655201 in words is "two hundred sixty-one million, six hundred fifty-five thousand, two hundred one".