1212331981 has 18 divisors (see below), whose sum is σ = 1443931182. Its totient is φ = 1014899760.

The previous prime is 1212331957. The next prime is 1212331997. The reversal of 1212331981 is 1891332121.

It can be written as a sum of positive squares in only one way, i.e., 817674025 + 394657956 = 28595^2 + 19866^2 .

It is not a de Polignac number, because 1212331981 - 2⁵ = 1212331949 is a prime.

It is a super-2 number, since 2×1212331981² = 2939497664310768722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212331481) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 83911 + ... + 97291.

It is an arithmetic number, because the mean of its divisors is an integer number (80218399).

Almost surely, 2^1212331981 is an apocalyptic number.

It is an amenable number.

1212331981 is a deficient number, since it is larger than the sum of its proper divisors (231599201).

1212331981 is an equidigital number, since it uses as much as digits as its factorization.

1212331981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13481 (or 13431 counting only the distinct ones).

The product of its digits is 2592, while the sum is 31.

The square root of 1212331981 is about 34818.5579971371. The cubic root of 1212331981 is about 1066.2863605927.

The spelling of 1212331981 in words is "one billion, two hundred twelve million, three hundred thirty-one thousand, nine hundred eighty-one".