100021021 has 4 divisors (see below), whose sum is σ = 100342944. Its totient is φ = 99699100.

The previous prime is 100021003. The next prime is 100021039. The reversal of 100021021 is 120120001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (100021003) and next prime (100021039).

It is a cyclic number.

It is not a de Polignac number, because 100021021 - 2¹⁵ = 99988253 is a prime.

It is a super-3 number, since 3×100021021³ (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100020995 and 100021013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100021091) 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, 160495 + ... + 161116.

It is an arithmetic number, because the mean of its divisors is an integer number (25085736).

Almost surely, 2^100021021 is an apocalyptic number.

It is an amenable number.

100021021 is a deficient number, since it is larger than the sum of its proper divisors (321923).

100021021 is an equidigital number, since it uses as much as digits as its factorization.

100021021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 321922.

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

The square root of 100021021 is about 10001.0509947705. The cubic root of 100021021 is about 464.1914046956.

Adding to 100021021 its reverse (120120001), we get a palindrome (220141022).

The spelling of 100021021 in words is "one hundred million, twenty-one thousand, twenty-one".