100199978 has 4 divisors (see below), whose sum is σ = 150299970. Its totient is φ = 50099988.

The previous prime is 100199947. The next prime is 100199993. The reversal of 100199978 is 879991001.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 84143929 + 16056049 = 9173^2 + 4007^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25049993 + ... + 25049996.

Almost surely, 2^100199978 is an apocalyptic number.

100199978 is a deficient number, since it is larger than the sum of its proper divisors (50099992).

100199978 is an equidigital number, since it uses as much as digits as its factorization.

100199978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50099991.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 100199978 is about 10009.9939060921. The cubic root of 100199978 is about 464.4680825599.

The spelling of 100199978 in words is "one hundred million, one hundred ninety-nine thousand, nine hundred seventy-eight".