1277999640 has 64 divisors (see below), whose sum is σ = 4260002400. Its totient is φ = 340799616.

The previous prime is 1277999617. The next prime is 1277999651. The reversal of 1277999640 is 469997721.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 590587 + ... + 592746.

Almost surely, 2^1277999640 is an apocalyptic number.

1277999640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1277999640 is an abundant number, since it is smaller than the sum of its proper divisors (2982002760).

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

1277999640 is a wasteful number, since it uses less digits than its factorization.

1277999640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183353 (or 1183343 counting only the distinct ones).

The product of its (nonzero) digits is 1714608, while the sum is 54.

The square root of 1277999640 is about 35749.1208283505. The cubic root of 1277999640 is about 1085.2011462819.

The spelling of 1277999640 in words is "one billion, two hundred seventy-seven million, nine hundred ninety-nine thousand, six hundred forty".