20909474 has 4 divisors (see below), whose sum is σ = 31364214. Its totient is φ = 10454736.

The previous prime is 20909453. The next prime is 20909479. The reversal of 20909474 is 47490902.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 47490902 = 2 ⋅23745451.

It can be written as a sum of positive squares in only one way, i.e., 11256025 + 9653449 = 3355^2 + 3107^2 .

It is a super-2 number, since 2×20909474² = 874412205913352, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20909479) 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, 5227367 + ... + 5227370.

Almost surely, 2^20909474 is an apocalyptic number.

20909474 is a deficient number, since it is larger than the sum of its proper divisors (10454740).

20909474 is a wasteful number, since it uses less digits than its factorization.

20909474 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10454739.

The product of its (nonzero) digits is 18144, while the sum is 35.

The square root of 20909474 is about 4572.6878310245. The cubic root of 20909474 is about 275.4954111157.

The spelling of 20909474 in words is "twenty million, nine hundred nine thousand, four hundred seventy-four".