20557471 has 16 divisors (see below), whose sum is σ = 24261120. Its totient is φ = 17207680.

The previous prime is 20557463. The next prime is 20557477. The reversal of 20557471 is 17475502.

It is a cyclic number.

It is not a de Polignac number, because 20557471 - 2³ = 20557463 is a prime.

It is a super-3 number, since 3×20557471³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20557477) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7620 + ... + 9958.

It is an arithmetic number, because the mean of its divisors is an integer number (1516320).

Almost surely, 2^20557471 is an apocalyptic number.

20557471 is a deficient number, since it is larger than the sum of its proper divisors (3703649).

20557471 is a wasteful number, since it uses less digits than its factorization.

20557471 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2414.

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

The square root of 20557471 is about 4534.0347374055. The cubic root of 20557471 is about 273.9407005777.

The spelling of 20557471 in words is "twenty million, five hundred fifty-seven thousand, four hundred seventy-one".