21100194 has 12 divisors (see below), whose sum is σ = 45717126. Its totient is φ = 7033392.

The previous prime is 21100193. The next prime is 21100207. The reversal of 21100194 is 49100112.

It can be written as a sum of positive squares in only one way, i.e., 19474569 + 1625625 = 4413^2 + 1275^2 .

It is a Harshad number since it is a multiple of its sum of digits (18), and also a Moran number because the ratio is a prime number: 1172233 = 21100194 / (2 + 1 + 1 + 0 + 0 + 1 + 9 + 4).

It is not an unprimeable number, because it can be changed into a prime (21100193) 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, 586099 + ... + 586134.

Almost surely, 2^21100194 is an apocalyptic number.

21100194 is an abundant number, since it is smaller than the sum of its proper divisors (24616932).

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

21100194 is a wasteful number, since it uses less digits than its factorization.

21100194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1172241 (or 1172238 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 18.

The square root of 21100194 is about 4593.4947480105. The cubic root of 21100194 is about 276.3304957099.

The spelling of 21100194 in words is "twenty-one million, one hundred thousand, one hundred ninety-four".