1242540889 has 2 divisors, whose sum is σ = 1242540890. Its totient is φ = 1242540888.

The previous prime is 1242540869. The next prime is 1242540899. The reversal of 1242540889 is 9880452421.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1150227225 + 92313664 = 33915^2 + 9608^2 .

It is a cyclic number.

It is not a de Polignac number, because 1242540889 - 2¹¹ = 1242538841 is a prime.

It is not a weakly prime, because it can be changed into another prime (1242540869) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621270444 + 621270445.

It is an arithmetic number, because the mean of its divisors is an integer number (621270445).

Almost surely, 2^1242540889 is an apocalyptic number.

It is an amenable number.

1242540889 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242540889 is an equidigital number, since it uses as much as digits as its factorization.

1242540889 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 184320, while the sum is 43.

The square root of 1242540889 is about 35249.6934596600. The cubic root of 1242540889 is about 1075.0703798162.

The spelling of 1242540889 in words is "one billion, two hundred forty-two million, five hundred forty thousand, eight hundred eighty-nine".