20070105561 has 99 divisors (see below), whose sum is σ = 33726738367. Its totient is φ = 11934196560.

The previous prime is 20070105521. The next prime is 20070105589. The reversal of 20070105561 is 16550107002.

The square root of 20070105561 is 141669.

It is a perfect power (a square), and thus also a powerful number.

20070105561 is a `hidden beast` number, since 20 + 0 + 70 + 10 + 5 + 561 = 666.

It can be written as a sum of positive squares in only one way, i.e., 14468481225 + 5601624336 = 120285^2 + 74844^2 .

It is a tau number, because it is divible by the number of its divisors (99).

It is a de Polignac number, because none of the positive numbers 2^k-20070105561 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20070105521) by changing a digit.

It is a polite number, since it can be written in 98 ways as a sum of consecutive naturals, for example, 378681211 + ... + 378681263.

Almost surely, 2^20070105561 is an apocalyptic number.

20070105561 is the 141669-th square number.

20070105561 is the 70835-th centered octagonal number.

It is an amenable number.

20070105561 is a deficient number, since it is larger than the sum of its proper divisors (13656632806).

20070105561 is an frugal number, since it uses more digits than its factorization.

20070105561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158 (or 67 counting only the distinct ones).

The product of its (nonzero) digits is 2100, while the sum is 27.

The spelling of 20070105561 in words is "twenty billion, seventy million, one hundred five thousand, five hundred sixty-one".