100778621 has 2 divisors, whose sum is σ = 100778622. Its totient is φ = 100778620.

The previous prime is 100778609. The next prime is 100778647. The reversal of 100778621 is 126877001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 64176121 + 36602500 = 8011^2 + 6050^2 .

It is a cyclic number.

It is not a de Polignac number, because 100778621 - 2¹⁰ = 100777597 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (100778651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 50389310 + 50389311.

It is an arithmetic number, because the mean of its divisors is an integer number (50389311).

Almost surely, 2^100778621 is an apocalyptic number.

It is an amenable number.

100778621 is a deficient number, since it is larger than the sum of its proper divisors (1).

100778621 is an equidigital number, since it uses as much as digits as its factorization.

100778621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4704, while the sum is 32.

The square root of 100778621 is about 10038.8555622641. The cubic root of 100778621 is about 465.3604497001.

The spelling of 100778621 in words is "one hundred million, seven hundred seventy-eight thousand, six hundred twenty-one".