99990778 has 4 divisors (see below), whose sum is σ = 149986170. Its totient is φ = 49995388.

The previous prime is 99990757. The next prime is 99990799. The reversal of 99990778 is 87709999.

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

It is an interprime number because it is at equal distance from previous prime (99990757) and next prime (99990799).

It can be written as a sum of positive squares in only one way, i.e., 53246209 + 46744569 = 7297^2 + 6837^2 .

It is a Smith number, since the sum of its digits (58) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 24997693 + ... + 24997696.

Almost surely, 2^99990778 is an apocalyptic number.

99990778 is a deficient number, since it is larger than the sum of its proper divisors (49995392).

99990778 is a wasteful number, since it uses less digits than its factorization.

99990778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49995391.

The product of its (nonzero) digits is 2571912, while the sum is 58.

The square root of 99990778 is about 9999.5388893688. The cubic root of 99990778 is about 464.1446146786.

The spelling of 99990778 in words is "ninety-nine million, nine hundred ninety thousand, seven hundred seventy-eight".