1213186421 has 2 divisors, whose sum is σ = 1213186422. Its totient is φ = 1213186420.

The previous prime is 1213186409. The next prime is 1213186441. The reversal of 1213186421 is 1246813121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1176147025 + 37039396 = 34295^2 + 6086^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213186421 - 2⁶ = 1213186357 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213186441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606593210 + 606593211.

It is an arithmetic number, because the mean of its divisors is an integer number (606593211).

Almost surely, 2^1213186421 is an apocalyptic number.

It is an amenable number.

1213186421 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213186421 is an equidigital number, since it uses as much as digits as its factorization.

1213186421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 29.

The square root of 1213186421 is about 34830.8257295172. The cubic root of 1213186421 is about 1066.5368045789.

Adding to 1213186421 its reverse (1246813121), we get a palindrome (2459999542).

The spelling of 1213186421 in words is "one billion, two hundred thirteen million, one hundred eighty-six thousand, four hundred twenty-one".