19918100 has 18 divisors (see below), whose sum is σ = 43222494. Its totient is φ = 7967200.

The previous prime is 19918097. The next prime is 19918103. The reversal of 19918100 is 181991.

It is an interprime number because it is at equal distance from previous prime (19918097) and next prime (19918103).

It can be written as a sum of positive squares in 3 ways, for example, as 5750404 + 14167696 = 2398^2 + 3764^2 .

It is a super-2 number, since 2×19918100² = 793461415220000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19918103) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 99491 + ... + 99690.

Almost surely, 2^19918100 is an apocalyptic number.

19918100 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19918100 is an abundant number, since it is smaller than the sum of its proper divisors (23304394).

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

19918100 is a wasteful number, since it uses less digits than its factorization.

19918100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199195 (or 199188 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 29.

The square root of 19918100 is about 4462.9698632189. The cubic root of 19918100 is about 271.0707367440.

The spelling of 19918100 in words is "nineteen million, nine hundred eighteen thousand, one hundred".