20647057 has 4 divisors (see below), whose sum is σ = 20666880. Its totient is φ = 20627236.

The previous prime is 20647049. The next prime is 20647093. The reversal of 20647057 is 75074602.

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 a cyclic number.

It is not a de Polignac number, because 20647057 - 2³ = 20647049 is a prime.

It is a super-2 number, since 2×20647057² = 852601925522498, which contains 22 as substring.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20647007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8257 + ... + 10462.

It is an arithmetic number, because the mean of its divisors is an integer number (5166720).

Almost surely, 2^20647057 is an apocalyptic number.

It is an amenable number.

20647057 is a deficient number, since it is larger than the sum of its proper divisors (19823).

20647057 is a wasteful number, since it uses less digits than its factorization.

20647057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19822.

The product of its (nonzero) digits is 11760, while the sum is 31.

The square root of 20647057 is about 4543.9032780199. The cubic root of 20647057 is about 274.3380530986.

The spelling of 20647057 in words is "twenty million, six hundred forty-seven thousand, fifty-seven".