642447720 has 192 divisors, whose sum is σ = 2216376000. Its totient is φ = 165525120.

The previous prime is 642447691. The next prime is 642447739. The reversal of 642447720 is 27744246.

It is a happy number.

642447720 is a `hidden beast` number, since 642 + 4 + 4 + 7 + 7 + 2 + 0 = 666.

642447720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1037571 + ... + 1038189.

It is an arithmetic number, because the mean of its divisors is an integer number (11543625).

Almost surely, 2^642447720 is an apocalyptic number.

642447720 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 642447720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1108188000).

642447720 is an abundant number, since it is smaller than the sum of its proper divisors (1573928280).

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

642447720 is a wasteful number, since it uses less digits than its factorization.

642447720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 701 (or 660 counting only the distinct ones).

The product of its (nonzero) digits is 75264, while the sum is 36.

The square root of 642447720 is about 25346.5524282889. The cubic root of 642447720 is about 862.8711143970.

The spelling of 642447720 in words is "six hundred forty-two million, four hundred forty-seven thousand, seven hundred twenty".