20656978 has 8 divisors (see below), whose sum is σ = 31030272. Its totient is φ = 10313556.

The previous prime is 20656973. The next prime is 20656991. The reversal of 20656978 is 87965602.

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 (20656973) 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, 5650 + ... + 8557.

It is an arithmetic number, because the mean of its divisors is an integer number (3878784).

Almost surely, 2^20656978 is an apocalyptic number.

20656978 is a deficient number, since it is larger than the sum of its proper divisors (10373294).

20656978 is a wasteful number, since it uses less digits than its factorization.

20656978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14936.

The product of its (nonzero) digits is 181440, while the sum is 43.

The square root of 20656978 is about 4544.9948294800. The cubic root of 20656978 is about 274.3819862688.

The spelling of 20656978 in words is "twenty million, six hundred fifty-six thousand, nine hundred seventy-eight".