265821397 has 4 divisors (see below), whose sum is σ = 269462860. Its totient is φ = 262179936.

The previous prime is 265821389. The next prime is 265821407. The reversal of 265821397 is 793128562.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 793128562 = 2 ⋅396564281.

It can be written as a sum of positive squares in 2 ways, for example, as 183846481 + 81974916 = 13559^2 + 9054^2 .

It is a cyclic number.

It is not a de Polignac number, because 265821397 - 2³ = 265821389 is a prime.

It is a super-2 number, since 2×265821397² = 141322030206063218, 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 (265821317) 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, 1820622 + ... + 1820767.

It is an arithmetic number, because the mean of its divisors is an integer number (67365715).

Almost surely, 2^265821397 is an apocalyptic number.

It is an amenable number.

265821397 is a deficient number, since it is larger than the sum of its proper divisors (3641463).

265821397 is an equidigital number, since it uses as much as digits as its factorization.

265821397 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3641462.

The product of its digits is 181440, while the sum is 43.

The square root of 265821397 is about 16304.0300846140. The cubic root of 265821397 is about 642.9787874942.

The spelling of 265821397 in words is "two hundred sixty-five million, eight hundred twenty-one thousand, three hundred ninety-seven".