1265885621 has 64 divisors (see below), whose sum is σ = 1809561600. Its totient is φ = 852768000.

The previous prime is 1265885573. The next prime is 1265885629.

1265885621 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1265885621 - 2¹⁸ = 1265623477 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1265885629) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1920590 + ... + 1921248.

It is an arithmetic number, because the mean of its divisors is an integer number (28274400).

Almost surely, 2^1265885621 is an apocalyptic number.

1265885621 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1265885621 is a deficient number, since it is larger than the sum of its proper divisors (543675979).

1265885621 is a wasteful number, since it uses less digits than its factorization.

1265885621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810.

The product of its digits is 230400, while the sum is 44.

The square root of 1265885621 is about 35579.2864037490. The cubic root of 1265885621 is about 1081.7614206397.

The spelling of 1265885621 in words is "one billion, two hundred sixty-five million, eight hundred eighty-five thousand, six hundred twenty-one".