20406121305 has 16 divisors (see below), whose sum is σ = 32973061824. Its totient is φ = 10775508800.

The previous prime is 20406121291. The next prime is 20406121313. The reversal of 20406121305 is 50312160402.

It is not a de Polignac number, because 20406121305 - 2⁵ = 20406121273 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6733179 + ... + 6736208.

It is an arithmetic number, because the mean of its divisors is an integer number (2060816364).

Almost surely, 2^20406121305 is an apocalyptic number.

It is an amenable number.

20406121305 is a deficient number, since it is larger than the sum of its proper divisors (12566940519).

20406121305 is a wasteful number, since it uses less digits than its factorization.

20406121305 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13469496.

The product of its (nonzero) digits is 1440, while the sum is 24.

Adding to 20406121305 its reverse (50312160402), we get a palindrome (70718281707).

The spelling of 20406121305 in words is "twenty billion, four hundred six million, one hundred twenty-one thousand, three hundred five".