21650071 has 4 divisors (see below), whose sum is σ = 21820672. Its totient is φ = 21479472.

The previous prime is 21650021. The next prime is 21650087. The reversal of 21650071 is 17005612.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21650071 - 2⁹ = 21649559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21650011) 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 3 ways as a sum of consecutive naturals, for example, 85110 + ... + 85363.

It is an arithmetic number, because the mean of its divisors is an integer number (5455168).

Almost surely, 2^21650071 is an apocalyptic number.

21650071 is a deficient number, since it is larger than the sum of its proper divisors (170601).

21650071 is a wasteful number, since it uses less digits than its factorization.

21650071 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170600.

The product of its (nonzero) digits is 420, while the sum is 22.

The square root of 21650071 is about 4652.9636792049. The cubic root of 21650071 is about 278.7103574638.

Adding to 21650071 its reverse (17005612), we get a palindrome (38655683).

The spelling of 21650071 in words is "twenty-one million, six hundred fifty thousand, seventy-one".