21730126 has 16 divisors (see below), whose sum is σ = 35877168. Its totient is φ = 9788800.

The previous prime is 21730109. The next prime is 21730133. The reversal of 21730126 is 62103712.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a junction number, because it is equal to n+sod(n) for n = 21730097 and 21730106.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1885 + ... + 6856.

It is an arithmetic number, because the mean of its divisors is an integer number (2242323).

Almost surely, 2^21730126 is an apocalyptic number.

21730126 is a deficient number, since it is larger than the sum of its proper divisors (14147042).

21730126 is a wasteful number, since it uses less digits than its factorization.

21730126 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8867.

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 21730126 is about 4661.5583231362. The cubic root of 21730126 is about 279.0534620039.

Adding to 21730126 its reverse (62103712), we get a palindrome (83833838).

The spelling of 21730126 in words is "twenty-one million, seven hundred thirty thousand, one hundred twenty-six".