21011210121 has 8 divisors (see below), whose sum is σ = 30561760224. Its totient is φ = 12734066720.

The previous prime is 21011210113. The next prime is 21011210141. The reversal of 21011210121 is 12101211012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21011210121 - 2³ = 21011210113 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21011210097 and 21011210106.

It is not an unprimeable number, because it can be changed into a prime (21011210111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 318351636 + ... + 318351701.

It is an arithmetic number, because the mean of its divisors is an integer number (3820220028).

Almost surely, 2^21011210121 is an apocalyptic number.

It is an amenable number.

21011210121 is a deficient number, since it is larger than the sum of its proper divisors (9550550103).

21011210121 is a wasteful number, since it uses less digits than its factorization.

21011210121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 636703351.

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

Adding to 21011210121 its reverse (12101211012), we get a palindrome (33112421133).

It can be divided in two parts, 21011 and 210121, that added together give a palindrome (231132).

The spelling of 21011210121 in words is "twenty-one billion, eleven million, two hundred ten thousand, one hundred twenty-one".