20217849815 has 8 divisors (see below), whose sum is σ = 25098020640. Its totient is φ = 15616545952.

The previous prime is 20217849809. The next prime is 20217849829. The reversal of 20217849815 is 51894871202.

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

It is a cyclic number.

It is not a de Polignac number, because 20217849815 - 2¹⁴ = 20217833431 is a prime.

It is a super-2 number, since 2×20217849815² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20217849815.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 69716579 + ... + 69716868.

It is an arithmetic number, because the mean of its divisors is an integer number (3137252580).

Almost surely, 2^20217849815 is an apocalyptic number.

20217849815 is a deficient number, since it is larger than the sum of its proper divisors (4880170825).

20217849815 is a wasteful number, since it uses less digits than its factorization.

20217849815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139433481.

The product of its (nonzero) digits is 322560, while the sum is 47.

The spelling of 20217849815 in words is "twenty billion, two hundred seventeen million, eight hundred forty-nine thousand, eight hundred fifteen".