1277997840 has 240 divisors, whose sum is σ = 5020000128. Its totient is φ = 285272064.

The previous prime is 1277997793. The next prime is 1277997841. The reversal of 1277997840 is 487997721.

It is a tau number, because it is divible by the number of its divisors (240).

It is not an unprimeable number, because it can be changed into a prime (1277997841) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 213772 + ... + 219668.

Almost surely, 2^1277997840 is an apocalyptic number.

1277997840 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 1277997840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2510000064).

1277997840 is an abundant number, since it is smaller than the sum of its proper divisors (3742002288).

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

1277997840 is a wasteful number, since it uses less digits than its factorization.

1277997840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5966 (or 5957 counting only the distinct ones).

The product of its (nonzero) digits is 1778112, while the sum is 54.

The square root of 1277997840 is about 35749.0956528973. The cubic root of 1277997840 is about 1085.2006367974.

The spelling of 1277997840 in words is "one billion, two hundred seventy-seven million, nine hundred ninety-seven thousand, eight hundred forty".