100120021 has 8 divisors (see below), whose sum is σ = 108010584. Its totient is φ = 92451840.

The previous prime is 100120003. The next prime is 100120037. The reversal of 100120021 is 120021001.

It can be written as a sum of positive squares in 4 ways, for example, as 39513796 + 60606225 = 6286^2 + 7785^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 100120021 - 2²⁵ = 66565589 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100119986 and 100120013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100120091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54660 + ... + 56461.

It is an arithmetic number, because the mean of its divisors is an integer number (13501323).

Almost surely, 2^100120021 is an apocalyptic number.

It is an amenable number.

100120021 is a deficient number, since it is larger than the sum of its proper divisors (7890563).

100120021 is a wasteful number, since it uses less digits than its factorization.

100120021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111191.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 100120021 is about 10005.9992504497. Note that the first 3 decimals coincide. The cubic root of 100120021 is about 464.3445051638.

Adding to 100120021 its reverse (120021001), we get a palindrome (220141022).

The spelling of 100120021 in words is "one hundred million, one hundred twenty thousand, twenty-one".