21181006 has 32 divisors (see below), whose sum is σ = 40135680. Its totient is φ = 8143200.

The previous prime is 21181003. The next prime is 21181007. The reversal of 21181006 is 60018112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21181001) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 11296 + ... + 13036.

It is an arithmetic number, because the mean of its divisors is an integer number (1254240).

Almost surely, 2^21181006 is an apocalyptic number.

21181006 is a deficient number, since it is larger than the sum of its proper divisors (18954674).

21181006 is a wasteful number, since it uses less digits than its factorization.

21181006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1840.

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 21181006 is about 4602.2826944898. The cubic root of 21181006 is about 276.6828206242.

Adding to 21181006 its reverse (60018112), we get a palindrome (81199118).

The spelling of 21181006 in words is "twenty-one million, one hundred eighty-one thousand, six".