20099978 has 8 divisors (see below), whose sum is σ = 30280068. Its totient is φ = 10006624.

The previous prime is 20099977. The next prime is 20099983. The reversal of 20099978 is 87999002.

It can be written as a sum of positive squares in 2 ways, for example, as 18258529 + 1841449 = 4273^2 + 1357^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (20099977) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21101 + ... + 22032.

Almost surely, 2^20099978 is an apocalyptic number.

20099978 is a deficient number, since it is larger than the sum of its proper divisors (10180090).

20099978 is a wasteful number, since it uses less digits than its factorization.

20099978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43368.

The product of its (nonzero) digits is 81648, while the sum is 44.

The square root of 20099978 is about 4483.2999007428. The cubic root of 20099978 is about 271.8933134799.

The spelling of 20099978 in words is "twenty million, ninety-nine thousand, nine hundred seventy-eight".