100821281 has 8 divisors (see below), whose sum is σ = 110118528. Its totient is φ = 91546000.

The previous prime is 100821233. The next prime is 100821289. The reversal of 100821281 is 182128001.

It is a happy number.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100821281 is a prime.

It is a super-2 number, since 2×100821281² = 20329861404961922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100821289) 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, 4991 + ... + 15051.

It is an arithmetic number, because the mean of its divisors is an integer number (13764816).

Almost surely, 2^100821281 is an apocalyptic number.

100821281 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

100821281 is a deficient number, since it is larger than the sum of its proper divisors (9297247).

100821281 is a wasteful number, since it uses less digits than its factorization.

100821281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10983.

The product of its (nonzero) digits is 256, while the sum is 23.

The square root of 100821281 is about 10040.9800816454. The cubic root of 100821281 is about 465.4261034273.

Adding to 100821281 its reverse (182128001), we get a palindrome (282949282).

The spelling of 100821281 in words is "one hundred million, eight hundred twenty-one thousand, two hundred eighty-one".