1247378643 has 36 divisors (see below), whose sum is σ = 2151893640. Its totient is φ = 712053720.

The previous prime is 1247378591. The next prime is 1247378677. The reversal of 1247378643 is 3468737421.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is not a de Polignac number, because 1247378643 - 2¹⁸ = 1247116499 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1247378683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 1284148 + ... + 1285118.

Almost surely, 2^1247378643 is an apocalyptic number.

1247378643 is a deficient number, since it is larger than the sum of its proper divisors (904514997).

1247378643 is an frugal number, since it uses more digits than its factorization.

1247378643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1965 (or 981 counting only the distinct ones).

The product of its digits is 677376, while the sum is 45.

The square root of 1247378643 is about 35318.2480171370. The cubic root of 1247378643 is about 1076.4638123686.

The spelling of 1247378643 in words is "one billion, two hundred forty-seven million, three hundred seventy-eight thousand, six hundred forty-three".