399668252640 has 48 divisors (see below), whose sum is σ = 1258954997328. Its totient is φ = 106578200576.

The previous prime is 399668252623. The next prime is 399668252647. The reversal of 399668252640 is 46252866993.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (48).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399668252647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 416320617 + ... + 416321576.

It is an arithmetic number, because the mean of its divisors is an integer number (26228229111).

Almost surely, 2^399668252640 is an apocalyptic number.

399668252640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

399668252640 is an abundant number, since it is smaller than the sum of its proper divisors (859286744688).

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

399668252640 is a wasteful number, since it uses less digits than its factorization.

399668252640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 832642211 (or 832642203 counting only the distinct ones).

The product of its (nonzero) digits is 33592320, while the sum is 60.

The spelling of 399668252640 in words is "three hundred ninety-nine billion, six hundred sixty-eight million, two hundred fifty-two thousand, six hundred forty".