100400021 has 8 divisors (see below), whose sum is σ = 102985344. Its totient is φ = 97821280.

The previous prime is 100400017. The next prime is 100400023. The reversal of 100400021 is 120004001.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 100400021 - 2² = 100400017 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 100399981 and 100400008.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100400023) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47636 + ... + 49698.

It is an arithmetic number, because the mean of its divisors is an integer number (12873168).

Almost surely, 2^100400021 is an apocalyptic number.

It is an amenable number.

100400021 is a deficient number, since it is larger than the sum of its proper divisors (2585323).

100400021 is a wasteful number, since it uses less digits than its factorization.

100400021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3291.

The product of its (nonzero) digits is 8, while the sum is 8.

The square root of 100400021 is about 10019.9810878065. The cubic root of 100400021 is about 464.7769709347.

Adding to 100400021 its reverse (120004001), we get a palindrome (220404022).

The spelling of 100400021 in words is "one hundred million, four hundred thousand, twenty-one".