1265780381 has 2 divisors, whose sum is σ = 1265780382. Its totient is φ = 1265780380.

The previous prime is 1265780377. The next prime is 1265780387. The reversal of 1265780381 is 1830875621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1262665156 + 3115225 = 35534^2 + 1765^2 .

It is a cyclic number.

It is not a de Polignac number, because 1265780381 - 2² = 1265780377 is a prime.

It is a super-2 number, since 2×1265780381² = 3204399945849010322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1265780387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 632890190 + 632890191.

It is an arithmetic number, because the mean of its divisors is an integer number (632890191).

Almost surely, 2^1265780381 is an apocalyptic number.

It is an amenable number.

1265780381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1265780381 is an equidigital number, since it uses as much as digits as its factorization.

1265780381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 41.

The square root of 1265780381 is about 35577.8074226055. The cubic root of 1265780381 is about 1081.7314422264.

The spelling of 1265780381 in words is "one billion, two hundred sixty-five million, seven hundred eighty thousand, three hundred eighty-one".