1279887840 has 864 divisors, whose sum is σ = 5929114464. Its totient is φ = 247726080.

The previous prime is 1279887751. The next prime is 1279887859. The reversal of 1279887840 is 487889721.

It is a happy number.

It is a super-2 number, since 2×1279887840² = 3276225765959731200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 13194672 + ... + 13194768.

It is an arithmetic number, because the mean of its divisors is an integer number (6862401).

Almost surely, 2^1279887840 is an apocalyptic number.

1279887840 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 1279887840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2964557232).

1279887840 is an abundant number, since it is smaller than the sum of its proper divisors (4649226624).

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

1279887840 is a wasteful number, since it uses less digits than its factorization.

1279887840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160 (or 142 counting only the distinct ones).

The product of its (nonzero) digits is 1806336, while the sum is 54.

The square root of 1279887840 is about 35775.5201220052. The cubic root of 1279887840 is about 1085.7353322658.

The spelling of 1279887840 in words is "one billion, two hundred seventy-nine million, eight hundred eighty-seven thousand, eight hundred forty".