123821111 has 2 divisors, whose sum is σ = 123821112. Its totient is φ = 123821110.

The previous prime is 123821083. The next prime is 123821177. The reversal of 123821111 is 111128321.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-123821111 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123821311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61910555 + 61910556.

It is an arithmetic number, because the mean of its divisors is an integer number (61910556).

Almost surely, 2^123821111 is an apocalyptic number.

123821111 is a deficient number, since it is larger than the sum of its proper divisors (1).

123821111 is an equidigital number, since it uses as much as digits as its factorization.

123821111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 20.

The square root of 123821111 is about 11127.4934733749. The cubic root of 123821111 is about 498.4231805080.

Adding to 123821111 its reverse (111128321), we get a palindrome (234949432).

The spelling of 123821111 in words is "one hundred twenty-three million, eight hundred twenty-one thousand, one hundred eleven".