261401263 has 16 divisors (see below), whose sum is σ = 275963904. Its totient is φ = 247307040.

The previous prime is 261401249. The next prime is 261401311. The reversal of 261401263 is 362104162.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261401263 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261401243) 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 15 ways as a sum of consecutive naturals, for example, 331756 + ... + 332542.

It is an arithmetic number, because the mean of its divisors is an integer number (17247744).

Almost surely, 2^261401263 is an apocalyptic number.

261401263 is a deficient number, since it is larger than the sum of its proper divisors (14562641).

261401263 is a wasteful number, since it uses less digits than its factorization.

261401263 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1062.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 261401263 is about 16167.9084299732. The cubic root of 261401263 is about 639.3949873242.

The spelling of 261401263 in words is "two hundred sixty-one million, four hundred one thousand, two hundred sixty-three".