100021731 has 4 divisors (see below), whose sum is σ = 133362312. Its totient is φ = 66681152.

The previous prime is 100021729. The next prime is 100021751. The reversal of 100021731 is 137120001.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 100021731 - 2¹ = 100021729 is a prime.

It is a super-2 number, since 2×100021731² = 20008693344472722, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 100021731.

It is not an unprimeable number, because it can be changed into a prime (100021711) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16670286 + ... + 16670291.

It is an arithmetic number, because the mean of its divisors is an integer number (33340578).

Almost surely, 2^100021731 is an apocalyptic number.

100021731 is a deficient number, since it is larger than the sum of its proper divisors (33340581).

100021731 is an equidigital number, since it uses as much as digits as its factorization.

100021731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33340580.

The product of its (nonzero) digits is 42, while the sum is 15.

The square root of 100021731 is about 10001.0864909769. The cubic root of 100021731 is about 464.1925030484.

Adding to 100021731 its reverse (137120001), we get a palindrome (237141732).

The spelling of 100021731 in words is "one hundred million, twenty-one thousand, seven hundred thirty-one".