21059057 has 2 divisors, whose sum is σ = 21059058. Its totient is φ = 21059056.

The previous prime is 21059041. The next prime is 21059063. The reversal of 21059057 is 75095012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20784481 + 274576 = 4559^2 + 524^2 .

It is a cyclic number.

It is not a de Polignac number, because 21059057 - 2⁴ = 21059041 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21059557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10529528 + 10529529.

It is an arithmetic number, because the mean of its divisors is an integer number (10529529).

Almost surely, 2^21059057 is an apocalyptic number.

It is an amenable number.

21059057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21059057 is an equidigital number, since it uses as much as digits as its factorization.

21059057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3150, while the sum is 29.

The square root of 21059057 is about 4589.0148180192. The cubic root of 21059057 is about 276.1508006335.

The spelling of 21059057 in words is "twenty-one million, fifty-nine thousand, fifty-seven".