21101099990 has 64 divisors (see below), whose sum is σ = 41813452800. Its totient is φ = 7631293824.

The previous prime is 21101099989. The next prime is 21101100061. The reversal of 21101099990 is 9999010112.

It is a happy number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2018096 + ... + 2028524.

It is an arithmetic number, because the mean of its divisors is an integer number (653335200).

Almost surely, 2^21101099990 is an apocalyptic number.

21101099990 is a deficient number, since it is larger than the sum of its proper divisors (20712352810).

21101099990 is a wasteful number, since it uses less digits than its factorization.

21101099990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10941.

The product of its (nonzero) digits is 13122, while the sum is 41.

The spelling of 21101099990 in words is "twenty-one billion, one hundred one million, ninety-nine thousand, nine hundred ninety".