1277391888 has 120 divisors (see below), whose sum is σ = 3774401280. Its totient is φ = 402174720.

The previous prime is 1277391853. The next prime is 1277391919. The reversal of 1277391888 is 8881937721.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1479745 + ... + 1480607.

It is an arithmetic number, because the mean of its divisors is an integer number (31453344).

Almost surely, 2^1277391888 is an apocalyptic number.

1277391888 is a gapful number since it is divisible by the number (18) 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 1277391888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1887200640).

1277391888 is an abundant number, since it is smaller than the sum of its proper divisors (2497009392).

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

1277391888 is a wasteful number, since it uses less digits than its factorization.

1277391888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1437 (or 1428 counting only the distinct ones).

The product of its digits is 1354752, while the sum is 54.

The square root of 1277391888 is about 35740.6195805277. The cubic root of 1277391888 is about 1085.0290967442.

The spelling of 1277391888 in words is "one billion, two hundred seventy-seven million, three hundred ninety-one thousand, eight hundred eighty-eight".