1221240353 has 4 divisors (see below), whose sum is σ = 1221684480. Its totient is φ = 1220796228.

The previous prime is 1221240343. The next prime is 1221240401. The reversal of 1221240353 is 3530421221.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3530421221 = 4283 ⋅824287.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221240353 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221240323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 217913 + ... + 223446.

It is an arithmetic number, because the mean of its divisors is an integer number (305421120).

Almost surely, 2^1221240353 is an apocalyptic number.

It is an amenable number.

1221240353 is a deficient number, since it is larger than the sum of its proper divisors (444127).

1221240353 is an equidigital number, since it uses as much as digits as its factorization.

1221240353 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444126.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 1221240353 is about 34946.2494840290. The cubic root of 1221240353 is about 1068.8917260929.

Adding to 1221240353 its reverse (3530421221), we get a palindrome (4751661574).

The spelling of 1221240353 in words is "one billion, two hundred twenty-one million, two hundred forty thousand, three hundred fifty-three".