21142165586 has 4 divisors (see below), whose sum is σ = 31713248382. Its totient is φ = 10571082792.

The previous prime is 21142165553. The next prime is 21142165589. The reversal of 21142165586 is 68556124112.

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., 15567303361 + 5574862225 = 124769^2 + 74665^2 .

It is not an unprimeable number, because it can be changed into a prime (21142165589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5285541395 + ... + 5285541398.

Almost surely, 2^21142165586 is an apocalyptic number.

21142165586 is a deficient number, since it is larger than the sum of its proper divisors (10571082796).

21142165586 is a wasteful number, since it uses less digits than its factorization.

21142165586 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10571082795.

The product of its digits is 115200, while the sum is 41.

Adding to 21142165586 its reverse (68556124112), we get a palindrome (89698289698).

The spelling of 21142165586 in words is "twenty-one billion, one hundred forty-two million, one hundred sixty-five thousand, five hundred eighty-six".