640438152816 has 360 divisors, whose sum is σ = 2127308291472. Its totient is φ = 165415219200.

The previous prime is 640438152811. The next prime is 640438152821. The reversal of 640438152816 is 618251834046.

It is an interprime number because it is at equal distance from previous prime (640438152811) and next prime (640438152821).

It is a super-2 number, since 2×640438152816² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640438152811) 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 71 ways as a sum of consecutive naturals, for example, 51504936 + ... + 51517368.

Almost surely, 2^640438152816 is an apocalyptic number.

640438152816 is a gapful number since it is divisible by the number (66) 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 640438152816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1063654145736).

640438152816 is an abundant number, since it is smaller than the sum of its proper divisors (1486870138656).

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

640438152816 is a wasteful number, since it uses less digits than its factorization.

640438152816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12661 (or 12637 counting only the distinct ones).

The product of its (nonzero) digits is 1105920, while the sum is 48.

The spelling of 640438152816 in words is "six hundred forty billion, four hundred thirty-eight million, one hundred fifty-two thousand, eight hundred sixteen".