646436736 has 192 divisors, whose sum is σ = 2049465600. Its totient is φ = 193950720.

The previous prime is 646436729. The next prime is 646436737. The reversal of 646436736 is 637634646.

It is a tau number, because it is divible by the number of its divisors (192).

It is a junction number, because it is equal to n+sod(n) for n = 646436691 and 646436700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646436737) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1761225 + ... + 1761591.

It is an arithmetic number, because the mean of its divisors is an integer number (10674300).

Almost surely, 2^646436736 is an apocalyptic number.

646436736 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 646436736, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1024732800).

646436736 is an abundant number, since it is smaller than the sum of its proper divisors (1403028864).

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

646436736 is a wasteful number, since it uses less digits than its factorization.

646436736 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 537 (or 522 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 45.

The square root of 646436736 is about 25425.1201767071. The cubic root of 646436736 is about 864.6533124585.

The spelling of 646436736 in words is "six hundred forty-six million, four hundred thirty-six thousand, seven hundred thirty-six".