21048857 has 2 divisors, whose sum is σ = 21048858. Its totient is φ = 21048856.

The previous prime is 21048829. The next prime is 21048889. The reversal of 21048857 is 75884012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12222016 + 8826841 = 3496^2 + 2971^2 .

It is a cyclic number.

It is not a de Polignac number, because 21048857 - 2⁶ = 21048793 is a prime.

It is not a weakly prime, because it can be changed into another prime (21048757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10524428 + 10524429.

It is an arithmetic number, because the mean of its divisors is an integer number (10524429).

Almost surely, 2^21048857 is an apocalyptic number.

It is an amenable number.

21048857 is a deficient number, since it is larger than the sum of its proper divisors (1).

21048857 is an equidigital number, since it uses as much as digits as its factorization.

21048857 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 21048857 is about 4587.9033337681. The cubic root of 21048857 is about 276.1062086866.

The spelling of 21048857 in words is "twenty-one million, forty-eight thousand, eight hundred fifty-seven".