1242543221 has 8 divisors (see below), whose sum is σ = 1268168088. Its totient is φ = 1217088000.

The previous prime is 1242543199. The next prime is 1242543223. The reversal of 1242543221 is 1223452421.

It can be written as a sum of positive squares in 4 ways, for example, as 25300900 + 1217242321 = 5030^2 + 34889^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1242543221 - 2³⁰ = 168801397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1242543223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27560 + ... + 56961.

It is an arithmetic number, because the mean of its divisors is an integer number (158521011).

Almost surely, 2^1242543221 is an apocalyptic number.

It is an amenable number.

1242543221 is a deficient number, since it is larger than the sum of its proper divisors (25624867).

1242543221 is an equidigital number, since it uses as much as digits as its factorization.

1242543221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84823.

The product of its digits is 3840, while the sum is 26.

The square root of 1242543221 is about 35249.7265379464. The cubic root of 1242543221 is about 1075.0710523796.

Adding to 1242543221 its reverse (1223452421), we get a palindrome (2465995642).

The spelling of 1242543221 in words is "one billion, two hundred forty-two million, five hundred forty-three thousand, two hundred twenty-one".