21654071 has 2 divisors, whose sum is σ = 21654072. Its totient is φ = 21654070.

The previous prime is 21654067. The next prime is 21654103. The reversal of 21654071 is 17045612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21654071 - 2² = 21654067 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21654071.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21654001) 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 as a sum of consecutive naturals, namely, 10827035 + 10827036.

It is an arithmetic number, because the mean of its divisors is an integer number (10827036).

Almost surely, 2^21654071 is an apocalyptic number.

21654071 is a deficient number, since it is larger than the sum of its proper divisors (1).

21654071 is an equidigital number, since it uses as much as digits as its factorization.

21654071 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1680, while the sum is 26.

The square root of 21654071 is about 4653.3934929254. The cubic root of 21654071 is about 278.7275209607.

Adding to 21654071 its reverse (17045612), we get a palindrome (38699683).

The spelling of 21654071 in words is "twenty-one million, six hundred fifty-four thousand, seventy-one".