21020570 has 8 divisors (see below), whose sum is σ = 37837044. Its totient is φ = 8408224.

The previous prime is 21020543. The next prime is 21020581. The reversal of 21020570 is 7502012.

It can be written as a sum of positive squares in 2 ways, for example, as 20912329 + 108241 = 4573^2 + 329^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 1051019 + ... + 1051038.

Almost surely, 2^21020570 is an apocalyptic number.

21020570 is a deficient number, since it is larger than the sum of its proper divisors (16816474).

21020570 is a wasteful number, since it uses less digits than its factorization.

21020570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2102064.

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 21020570 is about 4584.8195166222. The cubic root of 21020570 is about 275.9824693059.

Adding to 21020570 its reverse (7502012), we get a palindrome (28522582).

The spelling of 21020570 in words is "twenty-one million, twenty thousand, five hundred seventy".