1247784961 has 2 divisors, whose sum is σ = 1247784962. Its totient is φ = 1247784960.

The previous prime is 1247784959. The next prime is 1247784973. The reversal of 1247784961 is 1694877421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1092633025 + 155151936 = 33055^2 + 12456^2 .

It is a cyclic number.

It is not a de Polignac number, because 1247784961 - 2¹ = 1247784959 is a prime.

Together with 1247784959, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1247784911) 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 as a sum of consecutive naturals, namely, 623892480 + 623892481.

It is an arithmetic number, because the mean of its divisors is an integer number (623892481).

Almost surely, 2^1247784961 is an apocalyptic number.

It is an amenable number.

1247784961 is a deficient number, since it is larger than the sum of its proper divisors (1).

1247784961 is an equidigital number, since it uses as much as digits as its factorization.

1247784961 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 677376, while the sum is 49.

The square root of 1247784961 is about 35323.9997876798. Note that the first 3 decimals coincide. The cubic root of 1247784961 is about 1076.5806812235.

The spelling of 1247784961 in words is "one billion, two hundred forty-seven million, seven hundred eighty-four thousand, nine hundred sixty-one".