646751020 has 36 divisors (see below), whose sum is σ = 1387784160. Its totient is φ = 253178848.

The previous prime is 646750987. The next prime is 646751029. The reversal of 646751020 is 20157646.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646751029) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 36861 + ... + 51499.

It is an arithmetic number, because the mean of its divisors is an integer number (38549560).

Almost surely, 2^646751020 is an apocalyptic number.

It is an amenable number.

646751020 is an abundant number, since it is smaller than the sum of its proper divisors (741033140).

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

646751020 is a wasteful number, since it uses less digits than its factorization.

646751020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14742 (or 14693 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 31.

The square root of 646751020 is about 25431.3000060949. The cubic root of 646751020 is about 864.7934151988.

The spelling of 646751020 in words is "six hundred forty-six million, seven hundred fifty-one thousand, twenty".