100123021 has 4 divisors (see below), whose sum is σ = 101764444. Its totient is φ = 98481600.

The previous prime is 100122977. The next prime is 100123039. The reversal of 100123021 is 120321001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120321001 = 59 ⋅2039339.

It can be written as a sum of positive squares in 2 ways, for example, as 57547396 + 42575625 = 7586^2 + 6525^2 .

It is a cyclic number.

It is not a de Polignac number, because 100123021 - 2⁹ = 100122509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100122989 and 100123007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100123321) 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, 820620 + ... + 820741.

It is an arithmetic number, because the mean of its divisors is an integer number (25441111).

Almost surely, 2^100123021 is an apocalyptic number.

It is an amenable number.

100123021 is a deficient number, since it is larger than the sum of its proper divisors (1641423).

100123021 is an equidigital number, since it uses as much as digits as its factorization.

100123021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1641422.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 100123021 is about 10006.1491593919. The cubic root of 100123021 is about 464.3491429961.

Adding to 100123021 its reverse (120321001), we get a palindrome (220444022).

The spelling of 100123021 in words is "one hundred million, one hundred twenty-three thousand, twenty-one".