399820561 has 8 divisors (see below), whose sum is σ = 468082944. Its totient is φ = 334344480.

The previous prime is 399820543. The next prime is 399820601. The reversal of 399820561 is 165028993.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399820561 - 2¹¹ = 399818513 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399820541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 696265 + ... + 696838.

It is an arithmetic number, because the mean of its divisors is an integer number (58510368).

Almost surely, 2^399820561 is an apocalyptic number.

It is an amenable number.

399820561 is a deficient number, since it is larger than the sum of its proper divisors (68262383).

399820561 is a wasteful number, since it uses less digits than its factorization.

399820561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1393151.

The product of its (nonzero) digits is 116640, while the sum is 43.

The square root of 399820561 is about 19995.5135217878. The cubic root of 399820561 is about 736.6961067610.

The spelling of 399820561 in words is "three hundred ninety-nine million, eight hundred twenty thousand, five hundred sixty-one".