19979100 has 108 divisors (see below), whose sum is σ = 63641760. Its totient is φ = 5241600.

The previous prime is 19979083. The next prime is 19979101. The reversal of 19979100 is 197991.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19979101) by changing a digit.

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 35 ways as a sum of consecutive naturals, for example, 70960 + ... + 71240.

Almost surely, 2^19979100 is an apocalyptic number.

19979100 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 19979100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31820880).

19979100 is an abundant number, since it is smaller than the sum of its proper divisors (43662660).

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

19979100 is a wasteful number, since it uses less digits than its factorization.

19979100 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 380 (or 370 counting only the distinct ones).

The product of its (nonzero) digits is 5103, while the sum is 36.

The square root of 19979100 is about 4469.7986531834. The cubic root of 19979100 is about 271.3471764910.

The spelling of 19979100 in words is "nineteen million, nine hundred seventy-nine thousand, one hundred".