1263891664 has 40 divisors (see below), whose sum is σ = 2858174208. Its totient is φ = 530140800.

The previous prime is 1263891623. The next prime is 1263891683. The reversal of 1263891664 is 4661983621.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 114787 + ... + 125314.

Almost surely, 2^1263891664 is an apocalyptic number.

1263891664 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

1263891664 is an abundant number, since it is smaller than the sum of its proper divisors (1594282544).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1263891664 is a wasteful number, since it uses less digits than its factorization.

1263891664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240163 (or 240157 counting only the distinct ones).

The product of its digits is 373248, while the sum is 46.

The square root of 1263891664 is about 35551.2540425791. The cubic root of 1263891664 is about 1081.1931441074.

The spelling of 1263891664 in words is "one billion, two hundred sixty-three million, eight hundred ninety-one thousand, six hundred sixty-four".