1281989376 has 216 divisors, whose sum is σ = 3937602480. Its totient is φ = 411402240.

The previous prime is 1281989333. The next prime is 1281989389. The reversal of 1281989376 is 6739891821.

It is a tau number, because it is divible by the number of its divisors (216).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6642336 + ... + 6642528.

Almost surely, 2^1281989376 is an apocalyptic number.

1281989376 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1281989376, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1968801240).

1281989376 is an abundant number, since it is smaller than the sum of its proper divisors (2655613104).

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

1281989376 is an equidigital number, since it uses as much as digits as its factorization.

1281989376 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 280 (or 229 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 54.

The square root of 1281989376 is about 35804.8792205755. The cubic root of 1281989376 is about 1086.3292551916.

The spelling of 1281989376 in words is "one billion, two hundred eighty-one million, nine hundred eighty-nine thousand, three hundred seventy-six".