20453978 has 4 divisors (see below), whose sum is σ = 30680970. Its totient is φ = 10226988.

The previous prime is 20453921. The next prime is 20453987. The reversal of 20453978 is 87935402.

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., 13126129 + 7327849 = 3623^2 + 2707^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5113493 + ... + 5113496.

Almost surely, 2^20453978 is an apocalyptic number.

20453978 is a deficient number, since it is larger than the sum of its proper divisors (10226992).

20453978 is a wasteful number, since it uses less digits than its factorization.

20453978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10226991.

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 20453978 is about 4522.6074337709. The cubic root of 20453978 is about 273.4802247666.

The spelling of 20453978 in words is "twenty million, four hundred fifty-three thousand, nine hundred seventy-eight".