1247643648 has 288 divisors, whose sum is σ = 3935131200. Its totient is φ = 394149888.

The previous prime is 1247643643. The next prime is 1247643673. The reversal of 1247643648 is 8463467421.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×1247643648² = 3113229344789495808, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1247643641) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11446218 + ... + 11446326.

It is an arithmetic number, because the mean of its divisors is an integer number (13663650).

Almost surely, 2^1247643648 is an apocalyptic number.

1247643648 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 1247643648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1967565600).

1247643648 is an abundant number, since it is smaller than the sum of its proper divisors (2687487552).

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

1247643648 is an equidigital number, since it uses as much as digits as its factorization.

1247643648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169 (or 137 counting only the distinct ones).

The product of its digits is 774144, while the sum is 45.

The square root of 1247643648 is about 35321.9994904026. Note that the first 3 decimals coincide. The cubic root of 1247643648 is about 1076.5400383793.

The spelling of 1247643648 in words is "one billion, two hundred forty-seven million, six hundred forty-three thousand, six hundred forty-eight".