1281398940 has 120 divisors (see below), whose sum is σ = 4086009312. Its totient is φ = 336078720.

The previous prime is 1281398939. The next prime is 1281398941. The reversal of 1281398940 is 498931821.

It is an interprime number because it is at equal distance from previous prime (1281398939) and next prime (1281398941).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281398941) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 92337 + ... + 105303.

Almost surely, 2^1281398940 is an apocalyptic number.

1281398940 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 1281398940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2043004656).

1281398940 is an abundant number, since it is smaller than the sum of its proper divisors (2804610372).

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

1281398940 is a wasteful number, since it uses less digits than its factorization.

1281398940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13049 (or 13038 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The square root of 1281398940 is about 35796.6330818975. The cubic root of 1281398940 is about 1086.1624554747.

The spelling of 1281398940 in words is "one billion, two hundred eighty-one million, three hundred ninety-eight thousand, nine hundred forty".