20840978 has 8 divisors (see below), whose sum is σ = 31851468. Its totient is φ = 10223824.

The previous prime is 20840977. The next prime is 20840987. The reversal of 20840978 is 87904802.

It can be written as a sum of positive squares in 2 ways, for example, as 20043529 + 797449 = 4477^2 + 893^2 .

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 (20840977) 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, 98201 + ... + 98412.

Almost surely, 2^20840978 is an apocalyptic number.

20840978 is a deficient number, since it is larger than the sum of its proper divisors (11010490).

20840978 is a wasteful number, since it uses less digits than its factorization.

20840978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196668.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 20840978 is about 4565.1920003435. The cubic root of 20840978 is about 275.1942561363.

The spelling of 20840978 in words is "twenty million, eight hundred forty thousand, nine hundred seventy-eight".