20421646636265 has 32 divisors (see below), whose sum is σ = 29659001969664. Its totient is φ = 13177590451200.

The previous prime is 20421646636241. The next prime is 20421646636337. The reversal of 20421646636265 is 56263664612402.

It is not a de Polignac number, because 20421646636265 - 2⁸ = 20421646636009 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 1025552 + ... + 6472638.

It is an arithmetic number, because the mean of its divisors is an integer number (926843811552).

Almost surely, 2^{20421646636265} is an apocalyptic number.

It is an amenable number.

20421646636265 is a deficient number, since it is larger than the sum of its proper divisors (9237355333399).

20421646636265 is a wasteful number, since it uses less digits than its factorization.

20421646636265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5453417.

The product of its (nonzero) digits is 14929920, while the sum is 53.

The spelling of 20421646636265 in words is "twenty trillion, four hundred twenty-one billion, six hundred forty-six million, six hundred thirty-six thousand, two hundred sixty-five".