100100921 has 4 divisors (see below), whose sum is σ = 100222500. Its totient is φ = 99979344.

The previous prime is 100100887. The next prime is 100100927. The reversal of 100100921 is 129001001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 129001001 = 73 ⋅1767137.

It can be written as a sum of positive squares in 2 ways, for example, as 46240000 + 53860921 = 6800^2 + 7339^2 .

It is a cyclic number.

It is not a de Polignac number, because 100100921 - 2⁶ = 100100857 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100100896 and 100100905.

It is not an unprimeable number, because it can be changed into a prime (100100927) 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, 59546 + ... + 61203.

It is an arithmetic number, because the mean of its divisors is an integer number (25055625).

Almost surely, 2^100100921 is an apocalyptic number.

It is an amenable number.

100100921 is a deficient number, since it is larger than the sum of its proper divisors (121579).

100100921 is an equidigital number, since it uses as much as digits as its factorization.

100100921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121578.

The product of its (nonzero) digits is 18, while the sum is 14.

The square root of 100100921 is about 10005.0447775110. The cubic root of 100100921 is about 464.3149754587.

Adding to 100100921 its reverse (129001001), we get a palindrome (229101922).

The spelling of 100100921 in words is "one hundred million, one hundred thousand, nine hundred twenty-one".