646405659389952 has 6240 divisors, whose sum is σ = 2827088783861760. Its totient is φ = 144875166105600.

The previous prime is 646405659389951. The next prime is 646405659389977. The reversal of 646405659389952 is 259983956504646.

646405659389952 is a `hidden beast` number, since 6 + 4 + 6 + 40 + 565 + 9 + 3 + 8 + 9 + 9 + 5 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646405659389951) by changing a digit.

It is a polite number, since it can be written in 479 ways as a sum of consecutive naturals, for example, 20851795464177 + ... + 20851795464207.

Almost surely, 2^{646405659389952} is an apocalyptic number.

646405659389952 is a gapful number since it is divisible by the number (62) 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 646405659389952, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1413544391930880).

646405659389952 is an abundant number, since it is smaller than the sum of its proper divisors (2180683124471808).

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

646405659389952 is a wasteful number, since it uses less digits than its factorization.

646405659389952 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166 (or 90 counting only the distinct ones).

The product of its (nonzero) digits is 15116544000, while the sum is 81.

The spelling of 646405659389952 in words is "six hundred forty-six trillion, four hundred five billion, six hundred fifty-nine million, three hundred eighty-nine thousand, nine hundred fifty-two".