646369920 has 768 divisors, whose sum is σ = 2887073280. Its totient is φ = 129761280.

The previous prime is 646369907. The next prime is 646369939. The reversal of 646369920 is 29963646.

646369920 is a `hidden beast` number, since 6 + 4 + 636 + 9 + 9 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15765100 + ... + 15765140.

It is an arithmetic number, because the mean of its divisors is an integer number (3759210).

Almost surely, 2^646369920 is an apocalyptic number.

646369920 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 646369920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1443536640).

646369920 is an abundant number, since it is smaller than the sum of its proper divisors (2240703360).

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

646369920 is a wasteful number, since it uses less digits than its factorization.

646369920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 98 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 45.

The square root of 646369920 is about 25423.8061666620. The cubic root of 646369920 is about 864.6235211100.

The spelling of 646369920 in words is "six hundred forty-six million, three hundred sixty-nine thousand, nine hundred twenty".