21040570 has 8 divisors (see below), whose sum is σ = 37873044. Its totient is φ = 8416224.

The previous prime is 21040559. The next prime is 21040601. The reversal of 21040570 is 7504012.

It is a Cunningham number, because it is equal to 4587²+1.

It can be written as a sum of positive squares in 2 ways, for example, as 21040569 + 1 = 4587^2 + 1^2 .

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

It is a super-3 number, since 3×21040570³ (a number of 23 digits) contains 333 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1052019 + ... + 1052038.

Almost surely, 2^21040570 is an apocalyptic number.

21040570 is a deficient number, since it is larger than the sum of its proper divisors (16832474).

21040570 is a wasteful number, since it uses less digits than its factorization.

21040570 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2104064.

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21040570 is about 4587.0001090037. Note that the first 3 decimals coincide. The cubic root of 21040570 is about 276.0699693080.

Adding to 21040570 its reverse (7504012), we get a palindrome (28544582).

The spelling of 21040570 in words is "twenty-one million, forty thousand, five hundred seventy".