20146256561 has 8 divisors (see below), whose sum is σ = 20525187048. Its totient is φ = 19768896000.

The previous prime is 20146256539. The next prime is 20146256573. The reversal of 20146256561 is 16565264102.

It can be written as a sum of positive squares in 4 ways, for example, as 79834225 + 20066422336 = 8935^2 + 141656^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 20146256561 - 2³⁰ = 19072514737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20146256591) 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, 366560 + ... + 417921.

It is an arithmetic number, because the mean of its divisors is an integer number (2565648381).

Almost surely, 2^20146256561 is an apocalyptic number.

It is an amenable number.

20146256561 is a deficient number, since it is larger than the sum of its proper divisors (378930487).

20146256561 is an equidigital number, since it uses as much as digits as its factorization.

20146256561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784963.

The product of its (nonzero) digits is 86400, while the sum is 38.

The spelling of 20146256561 in words is "twenty billion, one hundred forty-six million, two hundred fifty-six thousand, five hundred sixty-one".