20533978 has 4 divisors (see below), whose sum is σ = 30800970. Its totient is φ = 10266988.

The previous prime is 20533973. The next prime is 20533979. The reversal of 20533978 is 87933502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 13227769 + 7306209 = 3637^2 + 2703^2 .

It is not an unprimeable number, because it can be changed into a prime (20533973) 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 as a sum of consecutive naturals, namely, 5133493 + ... + 5133496.

Almost surely, 2^20533978 is an apocalyptic number.

20533978 is a deficient number, since it is larger than the sum of its proper divisors (10266992).

20533978 is a wasteful number, since it uses less digits than its factorization.

20533978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10266991.

The product of its (nonzero) digits is 45360, while the sum is 37.

The square root of 20533978 is about 4531.4432579477. The cubic root of 20533978 is about 273.8363080027.

The spelling of 20533978 in words is "twenty million, five hundred thirty-three thousand, nine hundred seventy-eight".