1642787820 has 72 divisors (see below), whose sum is σ = 5001010560. Its totient is φ = 436504320.

The previous prime is 1642787819. The next prime is 1642787863. The reversal of 1642787820 is 287872461.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34341 + ... + 66819.

It is an arithmetic number, because the mean of its divisors is an integer number (69458480).

Almost surely, 2^1642787820 is an apocalyptic number.

1642787820 is a gapful number since it is divisible by the number (10) 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 1642787820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2500505280).

1642787820 is an abundant number, since it is smaller than the sum of its proper divisors (3358222740).

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

1642787820 is a wasteful number, since it uses less digits than its factorization.

1642787820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32775 (or 32770 counting only the distinct ones).

The product of its (nonzero) digits is 301056, while the sum is 45.

The square root of 1642787820 is about 40531.3190014833. The cubic root of 1642787820 is about 1179.9415416793.

The spelling of 1642787820 in words is "one billion, six hundred forty-two million, seven hundred eighty-seven thousand, eight hundred twenty".