646425780 has 384 divisors, whose sum is σ = 2492743680. Its totient is φ = 120821760.

The previous prime is 646425761. The next prime is 646425797. The reversal of 646425780 is 87524646.

646425780 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 (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 2822706 + ... + 2822934.

It is an arithmetic number, because the mean of its divisors is an integer number (6491520).

Almost surely, 2^646425780 is an apocalyptic number.

646425780 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 646425780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1246371840).

646425780 is an abundant number, since it is smaller than the sum of its proper divisors (1846317900).

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

646425780 is a wasteful number, since it uses less digits than its factorization.

646425780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 319 (or 317 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 42.

The square root of 646425780 is about 25424.9047195855. The cubic root of 646425780 is about 864.6484276313.

It can be divided in two parts, 646 and 425780, that added together give a triangular number (426426 = T₉₂₃).

The spelling of 646425780 in words is "six hundred forty-six million, four hundred twenty-five thousand, seven hundred eighty".