104139821 has 2 divisors, whose sum is σ = 104139822. Its totient is φ = 104139820.

The previous prime is 104139781. The next prime is 104139857. The reversal of 104139821 is 128931401.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 67404100 + 36735721 = 8210^2 + 6061^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-104139821 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (104159821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 52069910 + 52069911.

It is an arithmetic number, because the mean of its divisors is an integer number (52069911).

Almost surely, 2^104139821 is an apocalyptic number.

It is an amenable number.

104139821 is a deficient number, since it is larger than the sum of its proper divisors (1).

104139821 is an equidigital number, since it uses as much as digits as its factorization.

104139821 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 29.

The square root of 104139821 is about 10204.8920131474. The cubic root of 104139821 is about 470.4775905844.

The spelling of 104139821 in words is "one hundred four million, one hundred thirty-nine thousand, eight hundred twenty-one".