20403846561 has 16 divisors (see below), whose sum is σ = 31678210944. Its totient is φ = 11439352704.

The previous prime is 20403846553. The next prime is 20403846601. The reversal of 20403846561 is 16564830402.

It is not a de Polignac number, because 20403846561 - 2³ = 20403846553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20403846061) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9165036 + ... + 9167261.

It is an arithmetic number, because the mean of its divisors is an integer number (1979888184).

Almost surely, 2^20403846561 is an apocalyptic number.

20403846561 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

20403846561 is a deficient number, since it is larger than the sum of its proper divisors (11274364383).

20403846561 is a wasteful number, since it uses less digits than its factorization.

20403846561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18332360.

The product of its (nonzero) digits is 138240, while the sum is 39.

The spelling of 20403846561 in words is "twenty billion, four hundred three million, eight hundred forty-six thousand, five hundred sixty-one".