19917081900 has 252 divisors, whose sum is σ = 66190576032. Its totient is φ = 5197322880.

The previous prime is 19917081889. The next prime is 19917081913. The reversal of 19917081900 is 918071991.

It is a super-2 number, since 2×19917081900² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 3423394 + ... + 3429206.

It is an arithmetic number, because the mean of its divisors is an integer number (262661016).

Almost surely, 2^19917081900 is an apocalyptic number.

19917081900 is a gapful number since it is divisible by the number (10) 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 19917081900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33095288016).

19917081900 is an abundant number, since it is smaller than the sum of its proper divisors (46273494132).

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

19917081900 is a wasteful number, since it uses less digits than its factorization.

19917081900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5892 (or 5870 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 45.

The spelling of 19917081900 in words is "nineteen billion, nine hundred seventeen million, eighty-one thousand, nine hundred".