21050057 has 12 divisors (see below), whose sum is σ = 24593220. Its totient is φ = 17964576.

The previous prime is 21050053. The next prime is 21050059. The reversal of 21050057 is 75005012.

It can be written as a sum of positive squares in 2 ways, for example, as 2637376 + 18412681 = 1624^2 + 4291^2 .

It is not a de Polignac number, because 21050057 - 2² = 21050053 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21050053) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12383 + ... + 13979.

It is an arithmetic number, because the mean of its divisors is an integer number (2049435).

Almost surely, 2^21050057 is an apocalyptic number.

It is an amenable number.

21050057 is a deficient number, since it is larger than the sum of its proper divisors (3543163).

21050057 is a wasteful number, since it uses less digits than its factorization.

21050057 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1880 (or 1873 counting only the distinct ones).

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 21050057 is about 4588.0341105968. The cubic root of 21050057 is about 276.1114555456. Note that the first 3 decimals are identical.

Adding to 21050057 its reverse (75005012), we get a palindrome (96055069).

It can be divided in two parts, 2105005 and 7, that added together give a palindrome (2105012).

The spelling of 21050057 in words is "twenty-one million, fifty thousand, fifty-seven".