100821531 has 8 divisors (see below), whose sum is σ = 135254080. Its totient is φ = 66801672.

The previous prime is 100821521. The next prime is 100821547. The reversal of 100821531 is 135128001.

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

It is not a de Polignac number, because 100821531 - 2¹⁵ = 100788763 is a prime.

It is a super-2 number, since 2×100821531² = 20329962226367922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 100821498 and 100821507.

It is not an unprimeable number, because it can be changed into a prime (100821521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102601 + ... + 103578.

It is an arithmetic number, because the mean of its divisors is an integer number (16906760).

Almost surely, 2^100821531 is an apocalyptic number.

100821531 is a deficient number, since it is larger than the sum of its proper divisors (34432549).

100821531 is a wasteful number, since it uses less digits than its factorization.

100821531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206345.

The product of its (nonzero) digits is 240, while the sum is 21.

The square root of 100821531 is about 10040.9925306217. The cubic root of 100821531 is about 465.4264881226.

Adding to 100821531 its reverse (135128001), we get a palindrome (235949532).

The spelling of 100821531 in words is "one hundred million, eight hundred twenty-one thousand, five hundred thirty-one".