2138391780 has 96 divisors (see below), whose sum is σ = 7063633920. Its totient is φ = 473005440.

The previous prime is 2138391743. The next prime is 2138391781. The reversal of 2138391780 is 871938312.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is not an unprimeable number, because it can be changed into a prime (2138391781) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 69100 + ... + 95139.

It is an arithmetic number, because the mean of its divisors is an integer number (73579520).

Almost surely, 2^2138391780 is an apocalyptic number.

2138391780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2138391780 is an abundant number, since it is smaller than the sum of its proper divisors (4925242140).

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

2138391780 is a wasteful number, since it uses less digits than its factorization.

2138391780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164289 (or 164287 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 42.

The square root of 2138391780 is about 46242.7484044796. The cubic root of 2138391780 is about 1288.3358506214.

The spelling of 2138391780 in words is "two billion, one hundred thirty-eight million, three hundred ninety-one thousand, seven hundred eighty".