20347978 has 8 divisors (see below), whose sum is σ = 34882272. Its totient is φ = 8720556.

The previous prime is 20347973. The next prime is 20347991. The reversal of 20347978 is 87974302.

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

It is a self number, because there is not a number n which added to its sum of digits gives 20347978.

It is not an unprimeable number, because it can be changed into a prime (20347973) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 726700 + ... + 726727.

It is an arithmetic number, because the mean of its divisors is an integer number (4360284).

Almost surely, 2^20347978 is an apocalyptic number.

20347978 is a deficient number, since it is larger than the sum of its proper divisors (14534294).

20347978 is a wasteful number, since it uses less digits than its factorization.

20347978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1453436.

The product of its (nonzero) digits is 84672, while the sum is 40.

The square root of 20347978 is about 4510.8733079083. The cubic root of 20347978 is about 273.0069814438.

The spelling of 20347978 in words is "twenty million, three hundred forty-seven thousand, nine hundred seventy-eight".