20571457 has 8 divisors (see below), whose sum is σ = 20980800. Its totient is φ = 20164560.

The previous prime is 20571449. The next prime is 20571493. The reversal of 20571457 is 75417502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20571457 - 2³ = 20571449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20571437) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34044 + ... + 34642.

It is an arithmetic number, because the mean of its divisors is an integer number (2622600).

Almost surely, 2^20571457 is an apocalyptic number.

It is an amenable number.

20571457 is a deficient number, since it is larger than the sum of its proper divisors (409343).

20571457 is an equidigital number, since it uses as much as digits as its factorization.

20571457 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1223.

The product of its (nonzero) digits is 9800, while the sum is 31.

The square root of 20571457 is about 4535.5768100651. The cubic root of 20571457 is about 274.0028104565.

Adding to 20571457 its reverse (75417502), we get a palindrome (95988959).

The spelling of 20571457 in words is "twenty million, five hundred seventy-one thousand, four hundred fifty-seven".