2138421780 has 144 divisors (see below), whose sum is σ = 7384051584. Its totient is φ = 495855360.

The previous prime is 2138421751. The next prime is 2138421787. The reversal of 2138421780 is 871248312.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2138421787) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 22062 + ... + 69018.

It is an arithmetic number, because the mean of its divisors is an integer number (51278136).

Almost surely, 2^2138421780 is an apocalyptic number.

2138421780 is a gapful number since it is divisible by the number (20) 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 2138421780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3692025792).

2138421780 is an abundant number, since it is smaller than the sum of its proper divisors (5245629804).

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

2138421780 is a wasteful number, since it uses less digits than its factorization.

2138421780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47006 (or 47001 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 2138421780 is about 46243.0727785254. The cubic root of 2138421780 is about 1288.3418753819.

The spelling of 2138421780 in words is "two billion, one hundred thirty-eight million, four hundred twenty-one thousand, seven hundred eighty".