1247840685 has 48 divisors (see below), whose sum is σ = 2662068864. Its totient is φ = 526559616.

The previous prime is 1247840677. The next prime is 1247840687. The reversal of 1247840685 is 5860487421.

It is not a de Polignac number, because 1247840685 - 2³ = 1247840677 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 1247840685.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1247840687) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 148267 + ... + 156456.

It is an arithmetic number, because the mean of its divisors is an integer number (55459768).

Almost surely, 2^1247840685 is an apocalyptic number.

1247840685 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1247840685 is an abundant number, since it is smaller than the sum of its proper divisors (1414228179).

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

1247840685 is a wasteful number, since it uses less digits than its factorization.

1247840685 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 304754 (or 304751 counting only the distinct ones).

The product of its (nonzero) digits is 430080, while the sum is 45.

The square root of 1247840685 is about 35324.7885343989. The cubic root of 1247840685 is about 1076.5967070855.

The spelling of 1247840685 in words is "one billion, two hundred forty-seven million, eight hundred forty thousand, six hundred eighty-five".