21111212001 has 32 divisors (see below), whose sum is σ = 31217366016. Its totient is φ = 12583800000.

The previous prime is 21111211991. The next prime is 21111212053. The reversal of 21111212001 is 10021211112.

It is not a de Polignac number, because 21111212001 - 2⁶ = 21111211937 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21111212201) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 482310 + ... + 524256.

It is an arithmetic number, because the mean of its divisors is an integer number (975542688).

Almost surely, 2^21111212001 is an apocalyptic number.

It is an amenable number.

21111212001 is a deficient number, since it is larger than the sum of its proper divisors (10106154015).

21111212001 is a wasteful number, since it uses less digits than its factorization.

21111212001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42213.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21111212001 its reverse (10021211112), we get a palindrome (31132423113).

The spelling of 21111212001 in words is "twenty-one billion, one hundred eleven million, two hundred twelve thousand, one".