20856434465 has 8 divisors (see below), whose sum is σ = 25270709568. Its totient is φ = 16523155440.

The previous prime is 20856434461. The next prime is 20856434483. The reversal of 20856434465 is 56443465802.

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

It is not a de Polignac number, because 20856434465 - 2² = 20856434461 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20856434461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20248451 + ... + 20249480.

It is an arithmetic number, because the mean of its divisors is an integer number (3158838696).

Almost surely, 2^20856434465 is an apocalyptic number.

It is an amenable number.

20856434465 is a deficient number, since it is larger than the sum of its proper divisors (4414275103).

20856434465 is a wasteful number, since it uses less digits than its factorization.

20856434465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40498039.

The product of its (nonzero) digits is 2764800, while the sum is 47.

The spelling of 20856434465 in words is "twenty billion, eight hundred fifty-six million, four hundred thirty-four thousand, four hundred sixty-five".