646999650 has 288 divisors, whose sum is σ = 2027870208. Its totient is φ = 152020800.

The previous prime is 646999643. The next prime is 646999681. The reversal of 646999650 is 56999646.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 6281499 + ... + 6281601.

It is an arithmetic number, because the mean of its divisors is an integer number (7041216).

Almost surely, 2^646999650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646999650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1013935104).

646999650 is an abundant number, since it is smaller than the sum of its proper divisors (1380870558).

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

646999650 is a wasteful number, since it uses less digits than its factorization.

646999650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 188 (or 171 counting only the distinct ones).

The product of its (nonzero) digits is 3149280, while the sum is 54.

The square root of 646999650 is about 25436.1878039930. The cubic root of 646999650 is about 864.9042182917.

The spelling of 646999650 in words is "six hundred forty-six million, nine hundred ninety-nine thousand, six hundred fifty".