100781381 has 4 divisors (see below), whose sum is σ = 102489600. Its totient is φ = 99073164.

The previous prime is 100781371. The next prime is 100781393. The reversal of 100781381 is 183187001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 183187001 = 1567 ⋅116903.

It is a cyclic number.

It is not a de Polignac number, because 100781381 - 2²² = 96587077 is a prime.

It is a super-2 number, since 2×100781381² = 20313773512534322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100781311) 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 3 ways as a sum of consecutive naturals, for example, 854021 + ... + 854138.

It is an arithmetic number, because the mean of its divisors is an integer number (25622400).

Almost surely, 2^100781381 is an apocalyptic number.

It is an amenable number.

100781381 is a deficient number, since it is larger than the sum of its proper divisors (1708219).

100781381 is an equidigital number, since it uses as much as digits as its factorization.

100781381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1708218.

The product of its (nonzero) digits is 1344, while the sum is 29.

The square root of 100781381 is about 10038.9930271915. The cubic root of 100781381 is about 465.3646978998.

The spelling of 100781381 in words is "one hundred million, seven hundred eighty-one thousand, three hundred eighty-one".