1243156729 has 2 divisors, whose sum is σ = 1243156730. Its totient is φ = 1243156728.

The previous prime is 1243156723. The next prime is 1243156741. The reversal of 1243156729 is 9276513421.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 788486400 + 454670329 = 28080^2 + 21323^2 .

It is a cyclic number.

It is not a de Polignac number, because 1243156729 - 2⁵ = 1243156697 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1243156691 and 1243156700.

It is not a weakly prime, because it can be changed into another prime (1243156723) 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, 621578364 + 621578365.

It is an arithmetic number, because the mean of its divisors is an integer number (621578365).

Almost surely, 2^1243156729 is an apocalyptic number.

It is an amenable number.

1243156729 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243156729 is an equidigital number, since it uses as much as digits as its factorization.

1243156729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 40.

The square root of 1243156729 is about 35258.4277726617. The cubic root of 1243156729 is about 1075.2479627024.

It can be divided in two parts, 124315 and 6729, that added together give a square (131044 = 362²).

The spelling of 1243156729 in words is "one billion, two hundred forty-three million, one hundred fifty-six thousand, seven hundred twenty-nine".