399945068640 has 576 divisors, whose sum is σ = 1527839179776. Its totient is φ = 98215483392.

The previous prime is 399945068591. The next prime is 399945068657. The reversal of 399945068640 is 46860549993.

399945068640 is a `hidden beast` number, since 3 + 9 + 9 + 9 + 4 + 506 + 86 + 40 = 666.

It is a super-2 number, since 2×399945068640² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 327019069 + ... + 327020291.

It is an arithmetic number, because the mean of its divisors is an integer number (2652498576).

Almost surely, 2^399945068640 is an apocalyptic number.

399945068640 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 399945068640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (763919589888).

399945068640 is an abundant number, since it is smaller than the sum of its proper divisors (1127894111136).

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

399945068640 is a wasteful number, since it uses less digits than its factorization.

399945068640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1913 (or 1893 counting only the distinct ones).

The product of its (nonzero) digits is 50388480, while the sum is 63.

The spelling of 399945068640 in words is "three hundred ninety-nine billion, nine hundred forty-five million, sixty-eight thousand, six hundred forty".