21499057 has 2 divisors, whose sum is σ = 21499058. Its totient is φ = 21499056.

The previous prime is 21499039. The next prime is 21499081. The reversal of 21499057 is 75099412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21492496 + 6561 = 4636^2 + 81^2 .

It is a cyclic number.

It is not a de Polignac number, because 21499057 - 2¹¹ = 21497009 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21499757) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10749528 + 10749529.

It is an arithmetic number, because the mean of its divisors is an integer number (10749529).

Almost surely, 2^21499057 is an apocalyptic number.

It is an amenable number.

21499057 is a deficient number, since it is larger than the sum of its proper divisors (1).

21499057 is an equidigital number, since it uses as much as digits as its factorization.

21499057 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22680, while the sum is 37.

The square root of 21499057 is about 4636.7075603277. The cubic root of 21499057 is about 278.0608229148.

The spelling of 21499057 in words is "twenty-one million, four hundred ninety-nine thousand, fifty-seven".