265521961 has 4 divisors (see below), whose sum is σ = 265882000. Its totient is φ = 265161924.

The previous prime is 265521943. The next prime is 265521967. The reversal of 265521961 is 169125562.

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 265521961 - 2⁷ = 265521833 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 265521961.

It is not an unprimeable number, because it can be changed into a prime (265521967) 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, 178911 + ... + 180388.

It is an arithmetic number, because the mean of its divisors is an integer number (66470500).

Almost surely, 2^265521961 is an apocalyptic number.

It is an amenable number.

265521961 is a deficient number, since it is larger than the sum of its proper divisors (360039).

265521961 is an equidigital number, since it uses as much as digits as its factorization.

265521961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 360038.

The product of its digits is 32400, while the sum is 37.

The square root of 265521961 is about 16294.8446141717. The cubic root of 265521961 is about 642.7372677668.

The spelling of 265521961 in words is "two hundred sixty-five million, five hundred twenty-one thousand, nine hundred sixty-one".