21298057 has 6 divisors (see below), whose sum is σ = 23410394. Its totient is φ = 19361760.

The previous prime is 21298033. The next prime is 21298073. The reversal of 21298057 is 75089212.

It can be written as a sum of positive squares in only one way, i.e., 17842176 + 3455881 = 4224^2 + 1859^2 .

It is not a de Polignac number, because 21298057 - 2⁷ = 21297929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21298357) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 87888 + ... + 88129.

Almost surely, 2^21298057 is an apocalyptic number.

It is an amenable number.

21298057 is a deficient number, since it is larger than the sum of its proper divisors (2112337).

21298057 is a wasteful number, since it uses less digits than its factorization.

21298057 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176039 (or 176028 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 21298057 is about 4614.9817984473. The cubic root of 21298057 is about 277.1915551303.

The spelling of 21298057 in words is "twenty-one million, two hundred ninety-eight thousand, fifty-seven".