6420378780 has 144 divisors (see below), whose sum is σ = 20814524640. Its totient is φ = 1596248064.

The previous prime is 6420378779. The next prime is 6420378781. The reversal of 6420378780 is 878730246.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (6420378779) and next prime (6420378781).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6420378781) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 317616 + ... + 337224.

It is an arithmetic number, because the mean of its divisors is an integer number (144545310).

Almost surely, 2^6420378780 is an apocalyptic number.

6420378780 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 6420378780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10407262320).

6420378780 is an abundant number, since it is smaller than the sum of its proper divisors (14394145860).

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

6420378780 is a wasteful number, since it uses less digits than its factorization.

6420378780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19748 (or 19743 counting only the distinct ones).

The product of its (nonzero) digits is 451584, while the sum is 45.

The square root of 6420378780 is about 80127.2661458008. The cubic root of 6420378780 is about 1858.6040688132.

The spelling of 6420378780 in words is "six billion, four hundred twenty million, three hundred seventy-eight thousand, seven hundred eighty".