399806550 has 384 divisors, whose sum is σ = 1374912000. Its totient is φ = 83980800.

The previous prime is 399806509. The next prime is 399806567. The reversal of 399806550 is 55608993.

399806550 is a `hidden beast` number, since 3 + 9 + 98 + 0 + 6 + 550 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a junction number, because it is equal to n+sod(n) for n = 399806496 and 399806505.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 3667896 + ... + 3668004.

It is an arithmetic number, because the mean of its divisors is an integer number (3580500).

Almost surely, 2^399806550 is an apocalyptic number.

399806550 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 399806550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (687456000).

399806550 is an abundant number, since it is smaller than the sum of its proper divisors (975105450).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399806550 is a wasteful number, since it uses less digits than its factorization.

399806550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173 (or 162 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The square root of 399806550 is about 19995.1631651257. The cubic root of 399806550 is about 736.6875012591.

The spelling of 399806550 in words is "three hundred ninety-nine million, eight hundred six thousand, five hundred fifty".