21315135506206 has 8 divisors (see below), whose sum is σ = 32289264678024. Its totient is φ = 10552047280200.

The previous prime is 21315135506149. The next prime is 21315135506209. The reversal of 21315135506206 is 60260553151312.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21315135506209) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52760236200 + ... + 52760236603.

It is an arithmetic number, because the mean of its divisors is an integer number (4036158084753).

Almost surely, 2^{21315135506206} is an apocalyptic number.

21315135506206 is a deficient number, since it is larger than the sum of its proper divisors (10974129171818).

21315135506206 is a wasteful number, since it uses less digits than its factorization.

21315135506206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105520472906.

The product of its (nonzero) digits is 162000, while the sum is 40.

Adding to 21315135506206 its reverse (60260553151312), we get a palindrome (81575688657518).

The spelling of 21315135506206 in words is "twenty-one trillion, three hundred fifteen billion, one hundred thirty-five million, five hundred six thousand, two hundred six".