1281761280 has 448 divisors, whose sum is σ = 4875580800. Its totient is φ = 318504960.

The previous prime is 1281761267. The next prime is 1281761297. The reversal of 1281761280 is 821671821.

1281761280 is a `hidden beast` number, since 1 + 28 + 17 + 612 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 21012450 + ... + 21012510.

Almost surely, 2^1281761280 is an apocalyptic number.

1281761280 is a gapful number since it is divisible by the number (10) 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 1281761280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2437790400).

1281761280 is an abundant number, since it is smaller than the sum of its proper divisors (3593819520).

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

1281761280 is an equidigital number, since it uses as much as digits as its factorization.

1281761280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 1281761280 is about 35801.6938146787. The cubic root of 1281761280 is about 1086.2648235461.

The spelling of 1281761280 in words is "one billion, two hundred eighty-one million, seven hundred sixty-one thousand, two hundred eighty".