261900581 has 4 divisors (see below), whose sum is σ = 262102272. Its totient is φ = 261698892.

The previous prime is 261900577. The next prime is 261900593. The reversal of 261900581 is 185009162.

261900581 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 261900581 - 2² = 261900577 is a prime.

It is a super-2 number, since 2×261900581² = 137183828656275122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261900481) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98885 + ... + 101498.

It is an arithmetic number, because the mean of its divisors is an integer number (65525568).

Almost surely, 2^261900581 is an apocalyptic number.

It is an amenable number.

261900581 is a deficient number, since it is larger than the sum of its proper divisors (201691).

261900581 is a wasteful number, since it uses less digits than its factorization.

261900581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 201690.

The product of its (nonzero) digits is 4320, while the sum is 32.

The square root of 261900581 is about 16183.3427016794. The cubic root of 261900581 is about 639.8018437640.

The spelling of 261900581 in words is "two hundred sixty-one million, nine hundred thousand, five hundred eighty-one".