1221367831 has 2 divisors, whose sum is σ = 1221367832. Its totient is φ = 1221367830.

The previous prime is 1221367793. The next prime is 1221367913. The reversal of 1221367831 is 1387631221.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221367831 is a prime.

It is a super-2 number, since 2×1221367831² = 2983478757203289122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221367531) 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 as a sum of consecutive naturals, namely, 610683915 + 610683916.

It is an arithmetic number, because the mean of its divisors is an integer number (610683916).

Almost surely, 2^1221367831 is an apocalyptic number.

1221367831 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221367831 is an equidigital number, since it uses as much as digits as its factorization.

1221367831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 34.

The square root of 1221367831 is about 34948.0733517600. The cubic root of 1221367831 is about 1068.9289165439.

The spelling of 1221367831 in words is "one billion, two hundred twenty-one million, three hundred sixty-seven thousand, eight hundred thirty-one".