265661401 has 4 divisors (see below), whose sum is σ = 279643600. Its totient is φ = 251679204.

The previous prime is 265661393. The next prime is 265661423. The reversal of 265661401 is 104166562.

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 265661401 - 2³ = 265661393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (265661491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6991071 + ... + 6991108.

It is an arithmetic number, because the mean of its divisors is an integer number (69910900).

Almost surely, 2^265661401 is an apocalyptic number.

It is an amenable number.

265661401 is a deficient number, since it is larger than the sum of its proper divisors (13982199).

265661401 is a wasteful number, since it uses less digits than its factorization.

265661401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13982198.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 265661401 is about 16299.1227064526. The cubic root of 265661401 is about 642.8497601574.

The spelling of 265661401 in words is "two hundred sixty-five million, six hundred sixty-one thousand, four hundred one".