1263889491 has 8 divisors (see below), whose sum is σ = 1758455040. Its totient is φ = 805958472.

The previous prime is 1263889489. The next prime is 1263889547. The reversal of 1263889491 is 1949883621.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1263889491 - 2¹ = 1263889489 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1263889421) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9158551 + ... + 9158688.

It is an arithmetic number, because the mean of its divisors is an integer number (219806880).

Almost surely, 2^1263889491 is an apocalyptic number.

1263889491 is a deficient number, since it is larger than the sum of its proper divisors (494565549).

1263889491 is a wasteful number, since it uses less digits than its factorization.

1263889491 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18317265.

The product of its digits is 746496, while the sum is 51.

The square root of 1263889491 is about 35551.2234810562. The cubic root of 1263889491 is about 1081.1925244778.

The spelling of 1263889491 in words is "one billion, two hundred sixty-three million, eight hundred eighty-nine thousand, four hundred ninety-one".