1281990864 has 320 divisors, whose sum is σ = 4351721472. Its totient is φ = 315532800.

The previous prime is 1281990851. The next prime is 1281990869. The reversal of 1281990864 is 4680991821.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1281990869) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7676509 + ... + 7676675.

Almost surely, 2^1281990864 is an apocalyptic number.

1281990864 is a gapful number since it is divisible by the number (14) 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 1281990864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2175860736).

1281990864 is an abundant number, since it is smaller than the sum of its proper divisors (3069730608).

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

1281990864 is a wasteful number, since it uses less digits than its factorization.

1281990864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 294 (or 288 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 48.

The square root of 1281990864 is about 35804.8999998604. The cubic root of 1281990864 is about 1086.3296754908.

The spelling of 1281990864 in words is "one billion, two hundred eighty-one million, nine hundred ninety thousand, eight hundred sixty-four".