1221311031 has 16 divisors (see below), whose sum is σ = 1641523968. Its totient is φ = 807680000.

The previous prime is 1221310997. The next prime is 1221311057. The reversal of 1221311031 is 1301131221.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 1221311031 - 2⁶ = 1221310967 is a prime.

It is a super-2 number, since 2×1221311031² = 2983201268884565922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1221311031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1221311071) 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 15 ways as a sum of consecutive naturals, for example, 190366 + ... + 196676.

It is an arithmetic number, because the mean of its divisors is an integer number (102595248).

Almost surely, 2^1221311031 is an apocalyptic number.

1221311031 is a deficient number, since it is larger than the sum of its proper divisors (420212937).

1221311031 is a wasteful number, since it uses less digits than its factorization.

1221311031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6822.

The product of its (nonzero) digits is 36, while the sum is 15.

The square root of 1221311031 is about 34947.2607081013. The cubic root of 1221311031 is about 1068.9123460229.

Adding to 1221311031 its reverse (1301131221), we get a palindrome (2522442252).

The spelling of 1221311031 in words is "one billion, two hundred twenty-one million, three hundred eleven thousand, thirty-one".