1247781312 has 84 divisors (see below), whose sum is σ = 3583356816. Its totient is φ = 415134720.

The previous prime is 1247781307. The next prime is 1247781313. The reversal of 1247781312 is 2131877421.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1247781313) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 353637 + ... + 357147.

Almost surely, 2^1247781312 is an apocalyptic number.

1247781312 is a gapful number since it is divisible by the number (12) 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 1247781312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1791678408).

1247781312 is an abundant number, since it is smaller than the sum of its proper divisors (2335575504).

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

1247781312 is a wasteful number, since it uses less digits than its factorization.

1247781312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4146 (or 4133 counting only the distinct ones).

The product of its digits is 18816, while the sum is 36.

The square root of 1247781312 is about 35323.9481372057. The cubic root of 1247781312 is about 1076.5796317781.

The spelling of 1247781312 in words is "one billion, two hundred forty-seven million, seven hundred eighty-one thousand, three hundred twelve".