100440781 has 4 divisors (see below), whose sum is σ = 114789472. Its totient is φ = 86092092.

The previous prime is 100440749. The next prime is 100440787. The reversal of 100440781 is 187044001.

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: 187044001 = 7297 ⋅25633.

It is a cyclic number.

It is not a de Polignac number, because 100440781 - 2⁵ = 100440749 is a prime.

It is a super-2 number, since 2×100440781² = 20176700975779922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (100440787) 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, 7174335 + ... + 7174348.

It is an arithmetic number, because the mean of its divisors is an integer number (28697368).

Almost surely, 2^100440781 is an apocalyptic number.

It is an amenable number.

100440781 is a deficient number, since it is larger than the sum of its proper divisors (14348691).

100440781 is an equidigital number, since it uses as much as digits as its factorization.

100440781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14348690.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 100440781 is about 10022.0148173908. The cubic root of 100440781 is about 464.8398585253.

Adding to 100440781 its reverse (187044001), we get a palindrome (287484782).

The spelling of 100440781 in words is "one hundred million, four hundred forty thousand, seven hundred eighty-one".