399186493440 has 512 divisors, whose sum is σ = 1470215335680. Its totient is φ = 90596966400.

The previous prime is 399186493423. The next prime is 399186493441. The reversal of 399186493440 is 44394681993.

It is a tau number, because it is divible by the number of its divisors (512).

It is a Harshad number since it is a multiple of its sum of digits (60).

It is not an unprimeable number, because it can be changed into a prime (399186493441) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 622755520 + ... + 622756160.

Almost surely, 2^399186493440 is an apocalyptic number.

399186493440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399186493440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (735107667840).

399186493440 is an abundant number, since it is smaller than the sum of its proper divisors (1071028842240).

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

399186493440 is an equidigital number, since it uses as much as digits as its factorization.

399186493440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 867 (or 839 counting only the distinct ones).

The product of its (nonzero) digits is 20155392, while the sum is 60.

The spelling of 399186493440 in words is "three hundred ninety-nine billion, one hundred eighty-six million, four hundred ninety-three thousand, four hundred forty".