100405381 has 2 divisors, whose sum is σ = 100405382. Its totient is φ = 100405380.

The previous prime is 100405369. The next prime is 100405397. The reversal of 100405381 is 183504001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 81613156 + 18792225 = 9034^2 + 4335^2 .

It is a cyclic number.

It is not a de Polignac number, because 100405381 - 2¹¹ = 100403333 is a prime.

It is a super-2 number, since 2×100405381² = 20162481067510322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100405181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50202690 + 50202691.

It is an arithmetic number, because the mean of its divisors is an integer number (50202691).

Almost surely, 2^100405381 is an apocalyptic number.

It is an amenable number.

100405381 is a deficient number, since it is larger than the sum of its proper divisors (1).

100405381 is an equidigital number, since it uses as much as digits as its factorization.

100405381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 100405381 is about 10020.2485498115. The cubic root of 100405381 is about 464.7852417173.

Adding to 100405381 its reverse (183504001), we get a palindrome (283909382).

The spelling of 100405381 in words is "one hundred million, four hundred five thousand, three hundred eighty-one".