20918474 has 4 divisors (see below), whose sum is σ = 31377714. Its totient is φ = 10459236.

The previous prime is 20918467. The next prime is 20918479. The reversal of 20918474 is 47481902.

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., 16687225 + 4231249 = 4085^2 + 2057^2 .

It is not an unprimeable number, because it can be changed into a prime (20918479) 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, 5229617 + ... + 5229620.

Almost surely, 2^20918474 is an apocalyptic number.

20918474 is a deficient number, since it is larger than the sum of its proper divisors (10459240).

20918474 is a wasteful number, since it uses less digits than its factorization.

20918474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10459239.

The product of its (nonzero) digits is 16128, while the sum is 35.

The square root of 20918474 is about 4573.6718290669. The cubic root of 20918474 is about 275.5349323241.

The spelling of 20918474 in words is "twenty million, nine hundred eighteen thousand, four hundred seventy-four".