399396291840 has 1728 divisors, whose sum is σ = 1831422168576. Its totient is φ = 77970014208.

The previous prime is 399396291817. The next prime is 399396291863. The reversal of 399396291840 is 48192693993.

399396291840 is a `hidden beast` number, since 399 + 3 + 9 + 62 + 9 + 184 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (399396291817) and next prime (399396291863).

It is a Harshad number since it is a multiple of its sum of digits (63).

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, 1300964967 + ... + 1300965273.

It is an arithmetic number, because the mean of its divisors is an integer number (1059850792).

Almost surely, 2^399396291840 is an apocalyptic number.

399396291840 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 399396291840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (915711084288).

399396291840 is an abundant number, since it is smaller than the sum of its proper divisors (1432025876736).

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

399396291840 is a wasteful number, since it uses less digits than its factorization.

399396291840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 444 (or 427 counting only the distinct ones).

The product of its (nonzero) digits is 22674816, while the sum is 63.

The spelling of 399396291840 in words is "three hundred ninety-nine billion, three hundred ninety-six million, two hundred ninety-one thousand, eight hundred forty".