19939951900 has 72 divisors (see below), whose sum is σ = 47300722560. Its totient is φ = 7235928000.

The previous prime is 19939951897. The next prime is 19939951949. The reversal of 19939951900 is 915993991.

It is a super-2 number, since 2×19939951900² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (55).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 521641 + ... + 558559.

It is an arithmetic number, because the mean of its divisors is an integer number (656954480).

Almost surely, 2^19939951900 is an apocalyptic number.

19939951900 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 19939951900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23650361280).

19939951900 is an abundant number, since it is smaller than the sum of its proper divisors (27360770660).

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

19939951900 is a wasteful number, since it uses less digits than its factorization.

19939951900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37435 (or 37428 counting only the distinct ones).

The product of its (nonzero) digits is 885735, while the sum is 55.

The spelling of 19939951900 in words is "nineteen billion, nine hundred thirty-nine million, nine hundred fifty-one thousand, nine hundred".