6446921120640 has 3072 divisors, whose sum is σ = 31914525081600. Its totient is φ = 1195587993600.

The previous prime is 6446921120623. The next prime is 6446921120641. The reversal of 6446921120640 is 460211296446.

6446921120640 is a `hidden beast` number, since 6 + 4 + 469 + 2 + 1 + 120 + 64 + 0 = 666.

It is a super-2 number, since 2×6446921120640² (a number of 26 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6446921120641) by changing a digit.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 5898371934 + ... + 5898373026.

It is an arithmetic number, because the mean of its divisors is an integer number (10388842800).

Almost surely, 2^{6446921120640} is an apocalyptic number.

6446921120640 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 6446921120640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15957262540800).

6446921120640 is an abundant number, since it is smaller than the sum of its proper divisors (25467603960960).

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

6446921120640 is a wasteful number, since it uses less digits than its factorization.

6446921120640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1194 (or 1165 counting only the distinct ones).

The product of its (nonzero) digits is 497664, while the sum is 45.

The spelling of 6446921120640 in words is "six trillion, four hundred forty-six billion, nine hundred twenty-one million, one hundred twenty thousand, six hundred forty".