21940000 has 60 divisors (see below), whose sum is σ = 54024894. Its totient is φ = 8768000.

The previous prime is 21939997. The next prime is 21940027. The reversal of 21940000 is 4912.

It can be written as a sum of positive squares in 5 ways, for example, as 144 + 21939856 = 12^2 + 4684^2 .

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

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 9 ways as a sum of consecutive naturals, for example, 19452 + ... + 20548.

Almost surely, 2^21940000 is an apocalyptic number.

21940000 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 21940000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27012447).

21940000 is an abundant number, since it is smaller than the sum of its proper divisors (32084894).

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

21940000 is an equidigital number, since it uses as much as digits as its factorization.

21940000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1127 (or 1104 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 21940000 is about 4684.0153714521. The cubic root of 21940000 is about 279.9489702923.

Adding to 21940000 its reverse (4912), we get a palindrome (21944912).

The spelling of 21940000 in words is "twenty-one million, nine hundred forty thousand".