21730026 has 16 divisors (see below), whose sum is σ = 44635104. Its totient is φ = 7047504.

The previous prime is 21730021. The next prime is 21730031. The reversal of 21730026 is 62003712.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21730021) and next prime (21730031).

It is a junction number, because it is equal to n+sod(n) for n = 21729984 and 21730011.

It is not an unprimeable number, because it can be changed into a prime (21730021) by changing a digit.

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, 48720 + ... + 49163.

It is an arithmetic number, because the mean of its divisors is an integer number (2789694).

Almost surely, 2^21730026 is an apocalyptic number.

21730026 is an abundant number, since it is smaller than the sum of its proper divisors (22905078).

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

21730026 is a wasteful number, since it uses less digits than its factorization.

21730026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97925.

The product of its (nonzero) digits is 504, while the sum is 21.

The square root of 21730026 is about 4661.5475970969. The cubic root of 21730026 is about 279.0530339440.

Adding to 21730026 its reverse (62003712), we get a palindrome (83733738).

The spelling of 21730026 in words is "twenty-one million, seven hundred thirty thousand, twenty-six".