21190000 has 100 divisors (see below), whose sum is σ = 55588456. Its totient is φ = 7776000.

The previous prime is 21189977. The next prime is 21190003. The reversal of 21190000 is 9112.

It is a tau number, because it is divible by the number of its divisors (100).

It is a super-2 number, since 2×21190000² = 898032200000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21190003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 129919 + ... + 130081.

Almost surely, 2^21190000 is an apocalyptic number.

21190000 is a gapful number since it is divisible by the number (20) 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 21190000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27794228).

21190000 is an abundant number, since it is smaller than the sum of its proper divisors (34398456).

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

21190000 is a wasteful number, since it uses less digits than its factorization.

21190000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 204 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 13.

The square root of 21190000 is about 4603.2597145936. The cubic root of 21190000 is about 276.7219772967.

Adding to 21190000 its reverse (9112), we get a palindrome (21199112).

The spelling of 21190000 in words is "twenty-one million, one hundred ninety thousand".