100438991 has 2 divisors, whose sum is σ = 100438992. Its totient is φ = 100438990.

The previous prime is 100438981. The next prime is 100439011. The reversal of 100438991 is 199834001.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-100438991 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100438981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50219495 + 50219496.

It is an arithmetic number, because the mean of its divisors is an integer number (50219496).

Almost surely, 2^100438991 is an apocalyptic number.

100438991 is a deficient number, since it is larger than the sum of its proper divisors (1).

100438991 is an equidigital number, since it uses as much as digits as its factorization.

100438991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 35.

The square root of 100438991 is about 10021.9255135927. The cubic root of 100438991 is about 464.8370971361.

The spelling of 100438991 in words is "one hundred million, four hundred thirty-eight thousand, nine hundred ninety-one".