21100021006 has 16 divisors (see below), whose sum is σ = 32809239216. Its totient is φ = 10168937856.

The previous prime is 21100021001. The next prime is 21100021021. The reversal of 21100021006 is 60012000112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100021001) 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, 1324491 + ... + 1340326.

It is an arithmetic number, because the mean of its divisors is an integer number (2050577451).

Almost surely, 2^21100021006 is an apocalyptic number.

21100021006 is a deficient number, since it is larger than the sum of its proper divisors (11709218210).

21100021006 is a wasteful number, since it uses less digits than its factorization.

21100021006 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2664963.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21100021006 its reverse (60012000112), we get a palindrome (81112021118).

The spelling of 21100021006 in words is "twenty-one billion, one hundred million, twenty-one thousand, six".