21111212110 has 16 divisors (see below), whose sum is σ = 38001998736. Its totient is φ = 8444081088.

The previous prime is 21111212077. The next prime is 21111212123. The reversal of 21111212110 is 1121211112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 260194 + ... + 331546.

It is an arithmetic number, because the mean of its divisors is an integer number (2375124921).

Almost surely, 2^21111212110 is an apocalyptic number.

21111212110 is a deficient number, since it is larger than the sum of its proper divisors (16890786626).

21111212110 is a wasteful number, since it uses less digits than its factorization.

21111212110 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100947.

The product of its (nonzero) digits is 8, while the sum is 13.

Adding to 21111212110 its reverse (1121211112), we get a palindrome (22232423222).

The spelling of 21111212110 in words is "twenty-one billion, one hundred eleven million, two hundred twelve thousand, one hundred ten".