1278921920 has 84 divisors (see below), whose sum is σ = 3214445184. Its totient is φ = 484600320.

The previous prime is 1278921911. The next prime is 1278921949. The reversal of 1278921920 is 291298721.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 109985 + ... + 121055.

Almost surely, 2^1278921920 is an apocalyptic number.

1278921920 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 1278921920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1607222592).

1278921920 is an abundant number, since it is smaller than the sum of its proper divisors (1935523264).

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

1278921920 is a wasteful number, since it uses less digits than its factorization.

1278921920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11126 (or 11097 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 41.

The square root of 1278921920 is about 35762.0178401611. The cubic root of 1278921920 is about 1085.4621319188.

The spelling of 1278921920 in words is "one billion, two hundred seventy-eight million, nine hundred twenty-one thousand, nine hundred twenty".