100181921 has 12 divisors (see below), whose sum is σ = 120558420. Its totient is φ = 82908000.

The previous prime is 100181843. The next prime is 100181933. The reversal of 100181921 is 129181001.

It can be written as a sum of positive squares in 2 ways, for example, as 62236321 + 37945600 = 7889^2 + 6160^2 .

It is not a de Polignac number, because 100181921 - 2¹⁸ = 99919777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100181971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33830 + ... + 36671.

It is an arithmetic number, because the mean of its divisors is an integer number (10046535).

Almost surely, 2^100181921 is an apocalyptic number.

It is an amenable number.

100181921 is a deficient number, since it is larger than the sum of its proper divisors (20376499).

100181921 is an equidigital number, since it uses as much as digits as its factorization.

100181921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 70544 (or 70537 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 23.

The square root of 100181921 is about 10009.0919168524. The cubic root of 100181921 is about 464.4401803448.

The spelling of 100181921 in words is "one hundred million, one hundred eighty-one thousand, nine hundred twenty-one".