100840421 has 4 divisors (see below), whose sum is σ = 110007744. Its totient is φ = 91673100.

The previous prime is 100840417. The next prime is 100840433. The reversal of 100840421 is 124048001.

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 a cyclic number.

It is not a de Polignac number, because 100840421 - 2² = 100840417 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 100840393 and 100840402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100840021) 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, 4583645 + ... + 4583666.

It is an arithmetic number, because the mean of its divisors is an integer number (27501936).

Almost surely, 2^100840421 is an apocalyptic number.

100840421 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

100840421 is a deficient number, since it is larger than the sum of its proper divisors (9167323).

100840421 is an equidigital number, since it uses as much as digits as its factorization.

100840421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9167322.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 100840421 is about 10041.9331306278. The cubic root of 100840421 is about 465.4555538630.

Adding to 100840421 its reverse (124048001), we get a palindrome (224888422).

The spelling of 100840421 in words is "one hundred million, eight hundred forty thousand, four hundred twenty-one".