100513781 has 4 divisors (see below), whose sum is σ = 105804000. Its totient is φ = 95223564.

The previous prime is 100513759. The next prime is 100513789. The reversal of 100513781 is 187315001.

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: 187315001 = 6029 ⋅31069.

It is a cyclic number.

It is not a de Polignac number, because 100513781 - 2⁶ = 100513717 is a prime.

It is a super-2 number, since 2×100513781² = 20206040341831922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 100513781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100513789) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2645081 + ... + 2645118.

It is an arithmetic number, because the mean of its divisors is an integer number (26451000).

Almost surely, 2^100513781 is an apocalyptic number.

It is an amenable number.

100513781 is a deficient number, since it is larger than the sum of its proper divisors (5290219).

100513781 is an equidigital number, since it uses as much as digits as its factorization.

100513781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5290218.

The product of its (nonzero) digits is 840, while the sum is 26.

The square root of 100513781 is about 10025.6561381288. The cubic root of 100513781 is about 464.9524459020.

Adding to 100513781 its reverse (187315001), we get a palindrome (287828782).

The spelling of 100513781 in words is "one hundred million, five hundred thirteen thousand, seven hundred eighty-one".