6399740067840 has 1260 divisors, whose sum is σ = 26799720629976. Its totient is φ = 1462797729792.

The previous prime is 6399740067793. The next prime is 6399740067863. The reversal of 6399740067840 is 487600479936.

6399740067840 is a `hidden beast` number, since 6 + 3 + 9 + 97 + 400 + 67 + 84 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1260).

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 83 ways as a sum of consecutive naturals, for example, 914248581117 + ... + 914248581123.

Almost surely, 2^{6399740067840} is an apocalyptic number.

6399740067840 is a gapful number since it is divisible by the number (60) 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 6399740067840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13399860314988).

6399740067840 is an abundant number, since it is smaller than the sum of its proper divisors (20399980562136).

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

6399740067840 is an frugal number, since it uses more digits than its factorization.

6399740067840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86 (or 17 counting only the distinct ones).

The product of its (nonzero) digits is 54867456, while the sum is 63.

The spelling of 6399740067840 in words is "six trillion, three hundred ninety-nine billion, seven hundred forty million, sixty-seven thousand, eight hundred forty".