1321243521 has 24 divisors (see below), whose sum is σ = 1926190656. Its totient is φ = 805147200.

The previous prime is 1321243477. The next prime is 1321243531. The reversal of 1321243521 is 1253421231.

It is not a de Polignac number, because 1321243521 - 2⁶ = 1321243457 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1321243491 and 1321243500.

It is not an unprimeable number, because it can be changed into a prime (1321243531) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39571 + ... + 64871.

It is an arithmetic number, because the mean of its divisors is an integer number (80257944).

Almost surely, 2^1321243521 is an apocalyptic number.

It is an amenable number.

1321243521 is a deficient number, since it is larger than the sum of its proper divisors (604947135).

1321243521 is a wasteful number, since it uses less digits than its factorization.

1321243521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25433 (or 25420 counting only the distinct ones).

The product of its digits is 1440, while the sum is 24.

The square root of 1321243521 is about 36348.9136151275. The cubic root of 1321243521 is about 1097.3056706623.

Adding to 1321243521 its reverse (1253421231), we get a palindrome (2574664752).

The spelling of 1321243521 in words is "one billion, three hundred twenty-one million, two hundred forty-three thousand, five hundred twenty-one".