113521681 has 20 divisors (see below), whose sum is σ = 142660532. Its totient is φ = 89794656.

The previous prime is 113521633. The next prime is 113521693. The reversal of 113521681 is 186125311.

It can be written as a sum of positive squares in 2 ways, for example, as 8643600 + 104878081 = 2940^2 + 10241^2 .

It is a de Polignac number, because none of the positive numbers 2^k-113521681 is a prime.

It is a super-2 number, since 2×113521681² = 25774344114131522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (113521381) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 29395 + ... + 33031.

Almost surely, 2^113521681 is an apocalyptic number.

It is an amenable number.

113521681 is a deficient number, since it is larger than the sum of its proper divisors (29138851).

113521681 is an frugal number, since it uses more digits than its factorization.

113521681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3678 (or 3657 counting only the distinct ones).

The product of its digits is 1440, while the sum is 28.

The square root of 113521681 is about 10654.6553674908. The cubic root of 113521681 is about 484.2016567993.

Adding to 113521681 its reverse (186125311), we get a palindrome (299646992).

The spelling of 113521681 in words is "one hundred thirteen million, five hundred twenty-one thousand, six hundred eighty-one".