21471057 has 24 divisors (see below), whose sum is σ = 31958784. Its totient is φ = 13883904.

The previous prime is 21471041. The next prime is 21471067. The reversal of 21471057 is 75017412.

It is not a de Polignac number, because 21471057 - 2⁴ = 21471041 is a prime.

It is a super-2 number, since 2×21471057² = 922012577394498, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21471057.

It is not an unprimeable number, because it can be changed into a prime (21471067) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81508 + ... + 81770.

It is an arithmetic number, because the mean of its divisors is an integer number (1331616).

Almost surely, 2^21471057 is an apocalyptic number.

It is an amenable number.

21471057 is a deficient number, since it is larger than the sum of its proper divisors (10487727).

21471057 is a wasteful number, since it uses less digits than its factorization.

21471057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 509 (or 506 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 27.

The square root of 21471057 is about 4633.6871927224. The cubic root of 21471057 is about 277.9400566028.

Adding to 21471057 its reverse (75017412), we get a palindrome (96488469).

The spelling of 21471057 in words is "twenty-one million, four hundred seventy-one thousand, fifty-seven".