1263863866 has 4 divisors (see below), whose sum is σ = 1895795802. Its totient is φ = 631931932.

The previous prime is 1263863863. The next prime is 1263863891. The reversal of 1263863866 is 6683683621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 6683683621 = 29 ⋅230471849.

It can be written as a sum of positive squares in only one way, i.e., 1031758641 + 232105225 = 32121^2 + 15235^2 .

It is not an unprimeable number, because it can be changed into a prime (1263863863) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 315965965 + ... + 315965968.

Almost surely, 2^1263863866 is an apocalyptic number.

1263863866 is a deficient number, since it is larger than the sum of its proper divisors (631931936).

1263863866 is an equidigital number, since it uses as much as digits as its factorization.

1263863866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631931935.

The product of its digits is 1492992, while the sum is 49.

The square root of 1263863866 is about 35550.8630837565. The cubic root of 1263863866 is about 1081.1852174714.

The spelling of 1263863866 in words is "one billion, two hundred sixty-three million, eight hundred sixty-three thousand, eight hundred sixty-six".