1281322320 has 160 divisors (see below), whose sum is σ = 4049740800. Its totient is φ = 335081472.

The previous prime is 1281322313. The next prime is 1281322327. The reversal of 1281322320 is 232231821.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1281322313) and next prime (1281322327).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281322327) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4763146 + ... + 4763414.

It is an arithmetic number, because the mean of its divisors is an integer number (25310880).

Almost surely, 2^1281322320 is an apocalyptic number.

1281322320 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 1281322320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2024870400).

1281322320 is an abundant number, since it is smaller than the sum of its proper divisors (2768418480).

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

1281322320 is a wasteful number, since it uses less digits than its factorization.

1281322320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 597 (or 591 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 1281322320 is about 35795.5628535158. The cubic root of 1281322320 is about 1086.1408063683.

The spelling of 1281322320 in words is "one billion, two hundred eighty-one million, three hundred twenty-two thousand, three hundred twenty".