19801900 has 36 divisors (see below), whose sum is σ = 43590960. Its totient is φ = 7806400.

The previous prime is 19801883. The next prime is 19801909. The reversal of 19801900 is 910891.

It is a super-2 number, since 2×19801900² = 784230487220000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19801909) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5706 + ... + 8494.

It is an arithmetic number, because the mean of its divisors is an integer number (1210860).

Almost surely, 2^19801900 is an apocalyptic number.

19801900 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 19801900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21795480).

19801900 is an abundant number, since it is smaller than the sum of its proper divisors (23789060).

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

19801900 is a wasteful number, since it uses less digits than its factorization.

19801900 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2874 (or 2867 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 28.

The square root of 19801900 is about 4449.9325837590. The cubic root of 19801900 is about 270.5425760647.

The spelling of 19801900 in words is "nineteen million, eight hundred one thousand, nine hundred".