1263404561 has 2 divisors, whose sum is σ = 1263404562. Its totient is φ = 1263404560.

The previous prime is 1263404557. The next prime is 1263404567. The reversal of 1263404561 is 1654043621.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 951352336 + 312052225 = 30844^2 + 17665^2 .

It is a cyclic number.

It is not a de Polignac number, because 1263404561 - 2² = 1263404557 is a prime.

It is not a weakly prime, because it can be changed into another prime (1263404567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 631702280 + 631702281.

It is an arithmetic number, because the mean of its divisors is an integer number (631702281).

Almost surely, 2^1263404561 is an apocalyptic number.

It is an amenable number.

1263404561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1263404561 is an equidigital number, since it uses as much as digits as its factorization.

1263404561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 1263404561 is about 35544.4026676494. The cubic root of 1263404561 is about 1081.0542292223.

The spelling of 1263404561 in words is "one billion, two hundred sixty-three million, four hundred four thousand, five hundred sixty-one".