20431551605 has 8 divisors (see below), whose sum is σ = 24518706264. Its totient is φ = 16344678400.

The previous prime is 20431551601. The next prime is 20431551611. The reversal of 20431551605 is 50615513402.

It can be written as a sum of positive squares in 4 ways, for example, as 2115448036 + 18316103569 = 45994^2 + 135337^2 .

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

It is not a de Polignac number, because 20431551605 - 2² = 20431551601 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20431551601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 154925 + ... + 254685.

It is an arithmetic number, because the mean of its divisors is an integer number (3064838283).

Almost surely, 2^20431551605 is an apocalyptic number.

It is an amenable number.

20431551605 is a deficient number, since it is larger than the sum of its proper divisors (4087154659).

20431551605 is an equidigital number, since it uses as much as digits as its factorization.

20431551605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140727.

The product of its (nonzero) digits is 18000, while the sum is 32.

The spelling of 20431551605 in words is "twenty billion, four hundred thirty-one million, five hundred fifty-one thousand, six hundred five".