64406391993440 has 384 divisors, whose sum is σ = 180457494997248. Its totient is φ = 21261798604800.

The previous prime is 64406391993421. The next prime is 64406391993451. The reversal of 64406391993440 is 4439919360446.

It is a super-2 number, since 2×64406391993440² (a number of 28 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 63 ways as a sum of consecutive naturals, for example, 15875371892 + ... + 15875375948.

It is an arithmetic number, because the mean of its divisors is an integer number (469941393222).

Almost surely, 2^{64406391993440} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64406391993440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90228747498624).

64406391993440 is an abundant number, since it is smaller than the sum of its proper divisors (116051103003808).

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

64406391993440 is a wasteful number, since it uses less digits than its factorization.

64406391993440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8010 (or 8002 counting only the distinct ones).

The product of its (nonzero) digits is 60466176, while the sum is 62.

The spelling of 64406391993440 in words is "sixty-four trillion, four hundred six billion, three hundred ninety-one million, nine hundred ninety-three thousand, four hundred forty".