111957561 has 9 divisors (see below), whose sum is σ = 161762341. Its totient is φ = 74617212.

The previous prime is 111957553. The next prime is 111957569. The reversal of 111957561 is 165759111.

The square root of 111957561 is 10581.

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

111957561 is a `hidden beast` number, since 1 + 1 + 1 + 95 + 7 + 561 = 666.

It is an interprime number because it is at equal distance from previous prime (111957553) and next prime (111957569).

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 111957561 - 2³ = 111957553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111957569) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 29980 + ... + 33506.

Almost surely, 2^111957561 is an apocalyptic number.

111957561 is the 10581-st square number.

111957561 is the 5291-st centered octagonal number.

It is an amenable number.

111957561 is a deficient number, since it is larger than the sum of its proper divisors (49804780).

111957561 is an frugal number, since it uses more digits than its factorization.

111957561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7060 (or 3530 counting only the distinct ones).

The product of its digits is 9450, while the sum is 36.

The cubic root of 111957561 is about 481.9675617937.

Multiplying 111957561 by its sum of digits (36), we get a square (4030472196 = 63486²).

The spelling of 111957561 in words is "one hundred eleven million, nine hundred fifty-seven thousand, five hundred sixty-one".