123006640021 has 2 divisors, whose sum is σ = 123006640022. Its totient is φ = 123006640020.

The previous prime is 123006639983. The next prime is 123006640139. The reversal of 123006640021 is 120046600321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 93688639396 + 29318000625 = 306086^2 + 171225^2 .

It is a cyclic number.

It is not a de Polignac number, because 123006640021 - 2⁷ = 123006639893 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123006647021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61503320010 + 61503320011.

It is an arithmetic number, because the mean of its divisors is an integer number (61503320011).

Almost surely, 2^123006640021 is an apocalyptic number.

It is an amenable number.

123006640021 is a deficient number, since it is larger than the sum of its proper divisors (1).

123006640021 is an equidigital number, since it uses as much as digits as its factorization.

123006640021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1728, while the sum is 25.

The spelling of 123006640021 in words is "one hundred twenty-three billion, six million, six hundred forty thousand, twenty-one".