120100021 has 4 divisors (see below), whose sum is σ = 120152844. Its totient is φ = 120047200.

The previous prime is 120100003. The next prime is 120100027. The reversal of 120100021 is 120001021.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120001021 = 7 ⋅17143003.

It can be written as a sum of positive squares in 2 ways, for example, as 40640625 + 79459396 = 6375^2 + 8914^2 .

It is a cyclic number.

It is not a de Polignac number, because 120100021 - 2²¹ = 118002869 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 120099977 and 120100013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (120100027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22840 + ... + 27601.

It is an arithmetic number, because the mean of its divisors is an integer number (30038211).

Almost surely, 2^120100021 is an apocalyptic number.

It is an amenable number.

120100021 is a deficient number, since it is larger than the sum of its proper divisors (52823).

120100021 is an equidigital number, since it uses as much as digits as its factorization.

120100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52822.

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

The square root of 120100021 is about 10959.0155123533. The cubic root of 120100021 is about 493.3794173633.

Adding to 120100021 its reverse (120001021), we get a palindrome (240101042).

It can be divided in two parts, 1201000 and 21, that added together give a palindrome (1201021).

The spelling of 120100021 in words is "one hundred twenty million, one hundred thousand, twenty-one".