20471457 has 4 divisors (see below), whose sum is σ = 27295280. Its totient is φ = 13647636.

The previous prime is 20471447. The next prime is 20471459. The reversal of 20471457 is 75417402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20471457 - 2⁴ = 20471441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20471459) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3411907 + ... + 3411912.

It is an arithmetic number, because the mean of its divisors is an integer number (6823820).

Almost surely, 2^20471457 is an apocalyptic number.

It is an amenable number.

20471457 is a deficient number, since it is larger than the sum of its proper divisors (6823823).

20471457 is an equidigital number, since it uses as much as digits as its factorization.

20471457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6823822.

The product of its (nonzero) digits is 7840, while the sum is 30.

The square root of 20471457 is about 4524.5394240740. The cubic root of 20471457 is about 273.5581036656.

Adding to 20471457 its reverse (75417402), we get a palindrome (95888859).

The spelling of 20471457 in words is "twenty million, four hundred seventy-one thousand, four hundred fifty-seven".