20239978 has 32 divisors (see below), whose sum is σ = 35743680. Its totient is φ = 8496000.

The previous prime is 20239951. The next prime is 20239981. The reversal of 20239978 is 87993202.

It is a self number, because there is not a number n which added to its sum of digits gives 20239978.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16548 + ... + 17728.

It is an arithmetic number, because the mean of its divisors is an integer number (1116990).

Almost surely, 2^20239978 is an apocalyptic number.

20239978 is a deficient number, since it is larger than the sum of its proper divisors (15503702).

20239978 is a wasteful number, since it uses less digits than its factorization.

20239978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1254.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 20239978 is about 4498.8863066319. The cubic root of 20239978 is about 272.5231156218.

The spelling of 20239978 in words is "twenty million, two hundred thirty-nine thousand, nine hundred seventy-eight".