1212785381 has 2 divisors, whose sum is σ = 1212785382. Its totient is φ = 1212785380.

The previous prime is 1212785311. The next prime is 1212785417. The reversal of 1212785381 is 1835872121.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 962860900 + 249924481 = 31030^2 + 15809^2 .

It is a cyclic number.

It is not a de Polignac number, because 1212785381 - 2³⁰ = 139043557 is a prime.

It is a super-2 number, since 2×1212785381² = 2941696760734630322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1212785311) 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, 606392690 + 606392691.

It is an arithmetic number, because the mean of its divisors is an integer number (606392691).

Almost surely, 2^1212785381 is an apocalyptic number.

It is an amenable number.

1212785381 is a deficient number, since it is larger than the sum of its proper divisors (1).

1212785381 is an equidigital number, since it uses as much as digits as its factorization.

1212785381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 26880, while the sum is 38.

The square root of 1212785381 is about 34825.0682842116. The cubic root of 1212785381 is about 1066.4192708260.

The spelling of 1212785381 in words is "one billion, two hundred twelve million, seven hundred eighty-five thousand, three hundred eighty-one".