21580057 has 2 divisors, whose sum is σ = 21580058. Its totient is φ = 21580056.

The previous prime is 21580051. The next prime is 21580079. The reversal of 21580057 is 75008512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15335056 + 6245001 = 3916^2 + 2499^2 .

It is a cyclic number.

It is not a de Polignac number, because 21580057 - 2²³ = 13191449 is a prime.

It is not a weakly prime, because it can be changed into another prime (21580051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10790028 + 10790029.

It is an arithmetic number, because the mean of its divisors is an integer number (10790029).

Almost surely, 2^21580057 is an apocalyptic number.

It is an amenable number.

21580057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21580057 is an equidigital number, since it uses as much as digits as its factorization.

21580057 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2800, while the sum is 28.

The square root of 21580057 is about 4645.4339947953. The cubic root of 21580057 is about 278.4095932488.

Adding to 21580057 its reverse (75008512), we get a palindrome (96588569).

The spelling of 21580057 in words is "twenty-one million, five hundred eighty thousand, fifty-seven".