1265202561 has 32 divisors (see below), whose sum is σ = 2030635008. Its totient is φ = 685048320.

The previous prime is 1265202557. The next prime is 1265202581. The reversal of 1265202561 is 1652025621.

It is not a de Polignac number, because 1265202561 - 2² = 1265202557 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1265202511) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39441 + ... + 63921.

It is an arithmetic number, because the mean of its divisors is an integer number (63457344).

Almost surely, 2^1265202561 is an apocalyptic number.

It is an amenable number.

1265202561 is a deficient number, since it is larger than the sum of its proper divisors (765432447).

1265202561 is a wasteful number, since it uses less digits than its factorization.

1265202561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24621.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 1265202561 is about 35569.6859839949. The cubic root of 1265202561 is about 1081.5668161967.

It can be divided in two parts, 1 and 265202561, that added together give a palindrome (265202562).

The spelling of 1265202561 in words is "one billion, two hundred sixty-five million, two hundred two thousand, five hundred sixty-one".