399829861 has 4 divisors (see below), whose sum is σ = 417213792. Its totient is φ = 382445932.

The previous prime is 399829849. The next prime is 399829883. The reversal of 399829861 is 168928993.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 399829861 - 2¹⁵ = 399797093 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399829831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8691931 + ... + 8691976.

It is an arithmetic number, because the mean of its divisors is an integer number (104303448).

Almost surely, 2^399829861 is an apocalyptic number.

It is an amenable number.

399829861 is a deficient number, since it is larger than the sum of its proper divisors (17383931).

399829861 is a wasteful number, since it uses less digits than its factorization.

399829861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17383930.

The product of its digits is 1679616, while the sum is 55.

The square root of 399829861 is about 19995.7460726025. The cubic root of 399829861 is about 736.7018186739.

The spelling of 399829861 in words is "three hundred ninety-nine million, eight hundred twenty-nine thousand, eight hundred sixty-one".