21788142378 has 32 divisors (see below), whose sum is σ = 47010165696. Its totient is φ = 6706522368.

The previous prime is 21788142377. The next prime is 21788142401. The reversal of 21788142378 is 87324188712.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a self number, because there is not a number n which added to its sum of digits gives 21788142378.

It is not an unprimeable number, because it can be changed into a prime (21788142377) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2009776 + ... + 2020587.

It is an arithmetic number, because the mean of its divisors is an integer number (1469067678).

Almost surely, 2^21788142378 is an apocalyptic number.

21788142378 is an abundant number, since it is smaller than the sum of its proper divisors (25222023318).

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

21788142378 is a wasteful number, since it uses less digits than its factorization.

21788142378 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4030438.

The product of its digits is 1204224, while the sum is 51.

The spelling of 21788142378 in words is "twenty-one billion, seven hundred eighty-eight million, one hundred forty-two thousand, three hundred seventy-eight".