19997752820 has 54 divisors (see below), whose sum is σ = 42545543922. Its totient is φ = 7895637216.

The previous prime is 19997752813. The next prime is 19997752837. The reversal of 19997752820 is 2825779991.

It can be written as a sum of positive squares in only one way, i.e., 15998202256 + 3999550564 = 126484^2 + 63242^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 19997752820.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 65139107 + ... + 65139413.

It is an arithmetic number, because the mean of its divisors is an integer number (787880443).

Almost surely, 2^19997752820 is an apocalyptic number.

19997752820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19997752820 is an abundant number, since it is smaller than the sum of its proper divisors (22547791102).

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

19997752820 is an equidigital number, since it uses as much as digits as its factorization.

19997752820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829 (or 417 counting only the distinct ones).

The product of its (nonzero) digits is 5715360, while the sum is 59.

The spelling of 19997752820 in words is "nineteen billion, nine hundred ninety-seven million, seven hundred fifty-two thousand, eight hundred twenty".