1221303131 has 4 divisors (see below), whose sum is σ = 1247288352. Its totient is φ = 1195317912.

The previous prime is 1221303119. The next prime is 1221303133. The reversal of 1221303131 is 1313031221.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1313031221 = 151 ⋅8695571.

It is a de Polignac number, because none of the positive numbers 2^k-1221303131 is a prime.

It is a super-2 number, since 2×1221303131² = 2983162675580806322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1221303133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12992540 + ... + 12992633.

It is an arithmetic number, because the mean of its divisors is an integer number (311822088).

Almost surely, 2^1221303131 is an apocalyptic number.

1221303131 is a deficient number, since it is larger than the sum of its proper divisors (25985221).

1221303131 is an equidigital number, since it uses as much as digits as its factorization.

1221303131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25985220.

The product of its (nonzero) digits is 108, while the sum is 17.

The square root of 1221303131 is about 34947.1476804617. The cubic root of 1221303131 is about 1068.9100412795.

Adding to 1221303131 its reverse (1313031221), we get a palindrome (2534334352).

The spelling of 1221303131 in words is "one billion, two hundred twenty-one million, three hundred three thousand, one hundred thirty-one".