21371066 has 4 divisors (see below), whose sum is σ = 32056602. Its totient is φ = 10685532.

The previous prime is 21371047. The next prime is 21371069. The reversal of 21371066 is 66017312.

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

It can be written as a sum of positive squares in only one way, i.e., 15015625 + 6355441 = 3875^2 + 2521^2 .

It is not an unprimeable number, because it can be changed into a prime (21371069) by changing a digit.

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 as a sum of consecutive naturals, namely, 5342765 + ... + 5342768.

Almost surely, 2^21371066 is an apocalyptic number.

21371066 is a deficient number, since it is larger than the sum of its proper divisors (10685536).

21371066 is a wasteful number, since it uses less digits than its factorization.

21371066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10685535.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 21371066 is about 4622.8850299353. The cubic root of 21371066 is about 277.5079282425.

Adding to 21371066 its reverse (66017312), we get a palindrome (87388378).

The spelling of 21371066 in words is "twenty-one million, three hundred seventy-one thousand, sixty-six".