21710057 has 2 divisors, whose sum is σ = 21710058. Its totient is φ = 21710056.

The previous prime is 21710023. The next prime is 21710111. The reversal of 21710057 is 75001712.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16777216 + 4932841 = 4096^2 + 2221^2 .

It is a cyclic number.

It is not a de Polignac number, because 21710057 - 2¹⁴ = 21693673 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21710957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10855028 + 10855029.

It is an arithmetic number, because the mean of its divisors is an integer number (10855029).

Almost surely, 2^21710057 is an apocalyptic number.

It is an amenable number.

21710057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21710057 is an equidigital number, since it uses as much as digits as its factorization.

21710057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 490, while the sum is 23.

The square root of 21710057 is about 4659.4052195532. The cubic root of 21710057 is about 278.9675283269.

Adding to 21710057 its reverse (75001712), we get a palindrome (96711769).

The spelling of 21710057 in words is "twenty-one million, seven hundred ten thousand, fifty-seven".