399840029 has 2 divisors, whose sum is σ = 399840030. Its totient is φ = 399840028.

The previous prime is 399840011. The next prime is 399840037. The reversal of 399840029 is 920048993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 396607225 + 3232804 = 19915^2 + 1798^2 .

It is a cyclic number.

It is not a de Polignac number, because 399840029 - 2⁸ = 399839773 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 (399840059) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199920014 + 199920015.

It is an arithmetic number, because the mean of its divisors is an integer number (199920015).

Almost surely, 2^399840029 is an apocalyptic number.

It is an amenable number.

399840029 is a deficient number, since it is larger than the sum of its proper divisors (1).

399840029 is an equidigital number, since it uses as much as digits as its factorization.

399840029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 139968, while the sum is 44.

The square root of 399840029 is about 19996.0003250650. Note that the first 3 decimals coincide. The cubic root of 399840029 is about 736.7080635973.

The spelling of 399840029 in words is "three hundred ninety-nine million, eight hundred forty thousand, twenty-nine".