1242531521 has 32 divisors (see below), whose sum is σ = 1598130432. Its totient is φ = 937820160.

The previous prime is 1242531517. The next prime is 1242531533. The reversal of 1242531521 is 1251352421.

It is a cyclic number.

It is not a de Polignac number, because 1242531521 - 2² = 1242531517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1242531541) 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 in 31 ways as a sum of consecutive naturals, for example, 731345 + ... + 733041.

It is an arithmetic number, because the mean of its divisors is an integer number (49941576).

Almost surely, 2^1242531521 is an apocalyptic number.

1242531521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1242531521 is a deficient number, since it is larger than the sum of its proper divisors (355598911).

1242531521 is a wasteful number, since it uses less digits than its factorization.

1242531521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2009.

The product of its digits is 2400, while the sum is 26.

The square root of 1242531521 is about 35249.5605788214. The cubic root of 1242531521 is about 1075.0676780179.

Adding to 1242531521 its reverse (1251352421), we get a palindrome (2493883942).

Subtracting 1242531521 from its reverse (1251352421), we obtain a square (8820900 = 2970²).

The spelling of 1242531521 in words is "one billion, two hundred forty-two million, five hundred thirty-one thousand, five hundred twenty-one".