1265381681 has 2 divisors, whose sum is σ = 1265381682. Its totient is φ = 1265381680.

The previous prime is 1265381671. The next prime is 1265381687. The reversal of 1265381681 is 1861835621.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1147854400 + 117527281 = 33880^2 + 10841^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1265381681 is a prime.

It is a super-2 number, since 2×1265381681² = 3202381597220771522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1265381687) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 632690840 + 632690841.

It is an arithmetic number, because the mean of its divisors is an integer number (632690841).

Almost surely, 2^1265381681 is an apocalyptic number.

It is an amenable number.

1265381681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1265381681 is an equidigital number, since it uses as much as digits as its factorization.

1265381681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 41.

The square root of 1265381681 is about 35572.2037692353. The cubic root of 1265381681 is about 1081.6178544289.

The spelling of 1265381681 in words is "one billion, two hundred sixty-five million, three hundred eighty-one thousand, six hundred eighty-one".