1213311989 has 2 divisors, whose sum is σ = 1213311990. Its totient is φ = 1213311988.

The previous prime is 1213311973. The next prime is 1213312019. The reversal of 1213311989 is 9891133121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1143589489 + 69722500 = 33817^2 + 8350^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213311989 - 2⁴ = 1213311973 is a prime.

It is a super-2 number, since 2×1213311989² = 2944251965302272242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215311989) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606655994 + 606655995.

It is an arithmetic number, because the mean of its divisors is an integer number (606655995).

Almost surely, 2^1213311989 is an apocalyptic number.

It is an amenable number.

1213311989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213311989 is an equidigital number, since it uses as much as digits as its factorization.

1213311989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 38.

The square root of 1213311989 is about 34832.6282241234. The cubic root of 1213311989 is about 1066.5735997686.

The spelling of 1213311989 in words is "one billion, two hundred thirteen million, three hundred eleven thousand, nine hundred eighty-nine".