19979826390 has 64 divisors (see below), whose sum is σ = 56083737600. Its totient is φ = 5047533792.

The previous prime is 19979826389. The next prime is 19979826397. The reversal of 19979826390 is 9362897991.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19979826397) 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, 1942222 + ... + 1952481.

It is an arithmetic number, because the mean of its divisors is an integer number (876308400).

Almost surely, 2^19979826390 is an apocalyptic number.

19979826390 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19979826390 is an abundant number, since it is smaller than the sum of its proper divisors (36103911210).

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

19979826390 is a wasteful number, since it uses less digits than its factorization.

19979826390 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3894738 (or 3894732 counting only the distinct ones).

The product of its (nonzero) digits is 13226976, while the sum is 63.

The spelling of 19979826390 in words is "nineteen billion, nine hundred seventy-nine million, eight hundred twenty-six thousand, three hundred ninety".