1265888621 has 2 divisors, whose sum is σ = 1265888622. Its totient is φ = 1265888620.

The previous prime is 1265888597. The next prime is 1265888669. The reversal of 1265888621 is 1268885621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1236577225 + 29311396 = 35165^2 + 5414^2 .

It is a cyclic number.

It is not a de Polignac number, because 1265888621 - 2³⁰ = 192146797 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1265888671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 632944310 + 632944311.

It is an arithmetic number, because the mean of its divisors is an integer number (632944311).

Almost surely, 2^1265888621 is an apocalyptic number.

It is an amenable number.

1265888621 is a deficient number, since it is larger than the sum of its proper divisors (1).

1265888621 is an equidigital number, since it uses as much as digits as its factorization.

1265888621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 368640, while the sum is 47.

The square root of 1265888621 is about 35579.3285630856. The cubic root of 1265888621 is about 1081.7622751881.

The spelling of 1265888621 in words is "one billion, two hundred sixty-five million, eight hundred eighty-eight thousand, six hundred twenty-one".