123828721 has 2 divisors, whose sum is σ = 123828722. Its totient is φ = 123828720.

The previous prime is 123828713. The next prime is 123828737. The reversal of 123828721 is 127828321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81721600 + 42107121 = 9040^2 + 6489^2 .

It is a cyclic number.

It is not a de Polignac number, because 123828721 - 2³ = 123828713 is a prime.

It is not a weakly prime, because it can be changed into another prime (123828701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61914360 + 61914361.

It is an arithmetic number, because the mean of its divisors is an integer number (61914361).

Almost surely, 2^123828721 is an apocalyptic number.

It is an amenable number.

123828721 is a deficient number, since it is larger than the sum of its proper divisors (1).

123828721 is an equidigital number, since it uses as much as digits as its factorization.

123828721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 34.

The square root of 123828721 is about 11127.8354139518. The cubic root of 123828721 is about 498.4333912673.

The spelling of 123828721 in words is "one hundred twenty-three million, eight hundred twenty-eight thousand, seven hundred twenty-one".