646121646240 has 384 divisors, whose sum is σ = 2349308344320. Its totient is φ = 146214678528.

The previous prime is 646121646229. The next prime is 646121646241. The reversal of 646121646240 is 42646121646.

It is a super-2 number, since 2×646121646240² (a number of 24 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 646121646192 and 646121646201.

It is not an unprimeable number, because it can be changed into a prime (646121646241) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 151705231 + ... + 151709489.

It is an arithmetic number, because the mean of its divisors is an integer number (6117990480).

Almost surely, 2^646121646240 is an apocalyptic number.

646121646240 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 646121646240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1174654172160).

646121646240 is an abundant number, since it is smaller than the sum of its proper divisors (1703186698080).

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

646121646240 is a wasteful number, since it uses less digits than its factorization.

646121646240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4724 (or 4716 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 42.

Adding to 646121646240 its reverse (42646121646), we get a palindrome (688767767886).

The spelling of 646121646240 in words is "six hundred forty-six billion, one hundred twenty-one million, six hundred forty-six thousand, two hundred forty".