123781631 has 2 divisors, whose sum is σ = 123781632. Its totient is φ = 123781630.

The previous prime is 123781621. The next prime is 123781633. The reversal of 123781631 is 136187321.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 123781631 - 2¹⁴ = 123765247 is a prime.

It is a super-2 number, since 2×123781631² = 30643784346040322, which contains 22 as substring.

Together with 123781633, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123781633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61890815 + 61890816.

It is an arithmetic number, because the mean of its divisors is an integer number (61890816).

Almost surely, 2^123781631 is an apocalyptic number.

123781631 is a deficient number, since it is larger than the sum of its proper divisors (1).

123781631 is an equidigital number, since it uses as much as digits as its factorization.

123781631 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 32.

The square root of 123781631 is about 11125.7193475298. The cubic root of 123781631 is about 498.3702012845.

The spelling of 123781631 in words is "one hundred twenty-three million, seven hundred eighty-one thousand, six hundred thirty-one".