20974451878 has 4 divisors (see below), whose sum is σ = 31461677820. Its totient is φ = 10487225938.

The previous prime is 20974451873. The next prime is 20974451881. The reversal of 20974451878 is 87815447902.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20974451873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5243612968 + ... + 5243612971.

It is an arithmetic number, because the mean of its divisors is an integer number (7865419455).

Almost surely, 2^20974451878 is an apocalyptic number.

20974451878 is a deficient number, since it is larger than the sum of its proper divisors (10487225942).

20974451878 is a wasteful number, since it uses less digits than its factorization.

20974451878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10487225941.

The product of its (nonzero) digits is 4515840, while the sum is 55.

The spelling of 20974451878 in words is "twenty billion, nine hundred seventy-four million, four hundred fifty-one thousand, eight hundred seventy-eight".