20657856215 has 8 divisors (see below), whose sum is σ = 24794697840. Its totient is φ = 16522771392.

The previous prime is 20657856151. The next prime is 20657856217. The reversal of 20657856215 is 51265875602.

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 20657856215 - 2⁶ = 20657856151 is a prime.

It is a super-2 number, since 2×20657856215² (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 20657856215.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20657856217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 413189 + ... + 460478.

It is an arithmetic number, because the mean of its divisors is an integer number (3099337230).

Almost surely, 2^20657856215 is an apocalyptic number.

20657856215 is a deficient number, since it is larger than the sum of its proper divisors (4136841625).

20657856215 is an equidigital number, since it uses as much as digits as its factorization.

20657856215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 878401.

The product of its (nonzero) digits is 1008000, while the sum is 47.

The spelling of 20657856215 in words is "twenty billion, six hundred fifty-seven million, eight hundred fifty-six thousand, two hundred fifteen".