1231865653 has 2 divisors, whose sum is σ = 1231865654. Its totient is φ = 1231865652.

The previous prime is 1231865651. The next prime is 1231865681. The reversal of 1231865653 is 3565681321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1024448049 + 207417604 = 32007^2 + 14402^2 .

It is an emirp because it is prime and its reverse (3565681321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1231865653 - 2¹ = 1231865651 is a prime.

It is a super-2 number, since 2×1231865653² = 3034985974082232818, which contains 22 as substring.

Together with 1231865651, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1231865651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 615932826 + 615932827.

It is an arithmetic number, because the mean of its divisors is an integer number (615932827).

Almost surely, 2^1231865653 is an apocalyptic number.

It is an amenable number.

1231865653 is a deficient number, since it is larger than the sum of its proper divisors (1).

1231865653 is an equidigital number, since it uses as much as digits as its factorization.

1231865653 is an evil number, because the sum of its binary digits is even.

The product of its digits is 129600, while the sum is 40.

The square root of 1231865653 is about 35097.9437146964. The cubic root of 1231865653 is about 1071.9827135425.

The spelling of 1231865653 in words is "one billion, two hundred thirty-one million, eight hundred sixty-five thousand, six hundred fifty-three".