1263991992 has 16 divisors (see below), whose sum is σ = 3159980040. Its totient is φ = 421330656.

The previous prime is 1263991957. The next prime is 1263992029. The reversal of 1263991992 is 2991993621.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26333143 + ... + 26333190.

Almost surely, 2^1263991992 is an apocalyptic number.

1263991992 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1263991992 is an abundant number, since it is smaller than the sum of its proper divisors (1895988048).

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

1263991992 is a wasteful number, since it uses less digits than its factorization.

1263991992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52666342 (or 52666338 counting only the distinct ones).

The product of its digits is 472392, while the sum is 51.

The square root of 1263991992 is about 35552.6650477851. The cubic root of 1263991992 is about 1081.2217518008.

The spelling of 1263991992 in words is "one billion, two hundred sixty-three million, nine hundred ninety-one thousand, nine hundred ninety-two".