646029720 has 288 divisors, whose sum is σ = 2492071920. Its totient is φ = 144668160.

The previous prime is 646029719. The next prime is 646029749. The reversal of 646029720 is 27920646.

It is a happy number.

646029720 is a `hidden beast` number, since 646 + 0 + 2 + 9 + 7 + 2 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

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 71 ways as a sum of consecutive naturals, for example, 934575 + ... + 935265.

Almost surely, 2^646029720 is an apocalyptic number.

646029720 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 646029720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1246035960).

646029720 is an abundant number, since it is smaller than the sum of its proper divisors (1846042200).

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

646029720 is a wasteful number, since it uses less digits than its factorization.

646029720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 775 (or 761 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 36.

The square root of 646029720 is about 25417.1147064335. The cubic root of 646029720 is about 864.4718037868.

The spelling of 646029720 in words is "six hundred forty-six million, twenty-nine thousand, seven hundred twenty".