109881781 has 4 divisors (see below), whose sum is σ = 110337964. Its totient is φ = 109425600.

The previous prime is 109881721. The next prime is 109881799. The reversal of 109881781 is 187188901.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 51969681 + 57912100 = 7209^2 + 7610^2 .

It is a cyclic number.

It is not a de Polignac number, because 109881781 - 2¹⁷ = 109750709 is a prime.

It is a super-2 number, since 2×109881781² = 24148011591463922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (109881721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227730 + ... + 228211.

It is an arithmetic number, because the mean of its divisors is an integer number (27584491).

Almost surely, 2^109881781 is an apocalyptic number.

It is an amenable number.

109881781 is a deficient number, since it is larger than the sum of its proper divisors (456183).

109881781 is an equidigital number, since it uses as much as digits as its factorization.

109881781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 456182.

The product of its (nonzero) digits is 32256, while the sum is 43.

The square root of 109881781 is about 10482.4510969525. The cubic root of 109881781 is about 478.9702766441.

It can be divided in two parts, 10988 and 1781, that added together give a square (12769 = 113²).

The spelling of 109881781 in words is "one hundred nine million, eight hundred eighty-one thousand, seven hundred eighty-one".