100578721 has 2 divisors, whose sum is σ = 100578722. Its totient is φ = 100578720.

The previous prime is 100578719. The next prime is 100578727. The reversal of 100578721 is 127875001.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72063121 + 28515600 = 8489^2 + 5340^2 .

It is a cyclic number.

It is not a de Polignac number, because 100578721 - 2¹ = 100578719 is a prime.

Together with 100578719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (100578727) 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 as a sum of consecutive naturals, namely, 50289360 + 50289361.

It is an arithmetic number, because the mean of its divisors is an integer number (50289361).

Almost surely, 2^100578721 is an apocalyptic number.

It is an amenable number.

100578721 is a deficient number, since it is larger than the sum of its proper divisors (1).

100578721 is an equidigital number, since it uses as much as digits as its factorization.

100578721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3920, while the sum is 31.

The square root of 100578721 is about 10028.8943059542. The cubic root of 100578721 is about 465.0525565909.

The spelling of 100578721 in words is "one hundred million, five hundred seventy-eight thousand, seven hundred twenty-one".