100120983561 has 27 divisors (see below), whose sum is σ = 149819221461. Its totient is φ = 64427971104.

The previous prime is 100120983509. The next prime is 100120983601. The reversal of 100120983561 is 165389021001.

The square root of 100120983561 is 316419.

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

100120983561 is a `hidden beast` number, since 1 + 0 + 0 + 1 + 2 + 0 + 98 + 3 + 561 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 31611062025 + 68509921536 = 177795^2 + 261744^2 .

It is not a de Polignac number, because 100120983561 - 2⁹ = 100120983049 is a prime.

It is a super-2 number, since 2×100120983561² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (100120982561) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 27526635 + ... + 27530271.

Almost surely, 2^100120983561 is an apocalyptic number.

100120983561 is the 316419-th square number.

100120983561 is the 158210-th centered octagonal number.

It is an amenable number.

100120983561 is a deficient number, since it is larger than the sum of its proper divisors (49698237900).

100120983561 is an frugal number, since it uses more digits than its factorization.

100120983561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7338 (or 3669 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

Multiplying 100120983561 by its sum of digits (36), we get a square (3604355408196 = 1898514²).

It can be divided in two parts, 100120 and 983561, that added together give a square (1083681 = 1041²).

The spelling of 100120983561 in words is "one hundred billion, one hundred twenty million, nine hundred eighty-three thousand, five hundred sixty-one".