21006010 has 16 divisors (see below), whose sum is σ = 38833416. Its totient is φ = 8175168.

The previous prime is 21005987. The next prime is 21006017. The reversal of 21006010 is 1060012.

It can be written as a sum of positive squares in 4 ways, for example, as 18378369 + 2627641 = 4287^2 + 1621^2 .

It is a super-2 number, since 2×21006010² = 882504912240200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (21006017) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28017 + ... + 28756.

Almost surely, 2^21006010 is an apocalyptic number.

21006010 is a deficient number, since it is larger than the sum of its proper divisors (17827406).

21006010 is a wasteful number, since it uses less digits than its factorization.

21006010 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56817.

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 21006010 is about 4583.2313928057. The cubic root of 21006010 is about 275.9187343885.

Adding to 21006010 its reverse (1060012), we get a palindrome (22066022).

The spelling of 21006010 in words is "twenty-one million, six thousand, ten".