1643135231 has 2 divisors, whose sum is σ = 1643135232. Its totient is φ = 1643135230.

The previous prime is 1643135213. The next prime is 1643135237. The reversal of 1643135231 is 1325313461.

Together with previous prime (1643135213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1643135231 - 2¹⁴ = 1643118847 is a prime.

It is a super-2 number, since 2×1643135231² = 5399786774706846722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1643135194 and 1643135203.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1643135237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 821567615 + 821567616.

It is an arithmetic number, because the mean of its divisors is an integer number (821567616).

Almost surely, 2^1643135231 is an apocalyptic number.

1643135231 is a deficient number, since it is larger than the sum of its proper divisors (1).

1643135231 is an equidigital number, since it uses as much as digits as its factorization.

1643135231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6480, while the sum is 29.

The square root of 1643135231 is about 40535.6044854397. The cubic root of 1643135231 is about 1180.0247124481.

Adding to 1643135231 its reverse (1325313461), we get a palindrome (2968448692).

The spelling of 1643135231 in words is "one billion, six hundred forty-three million, one hundred thirty-five thousand, two hundred thirty-one".