20101211212121 has 8 divisors (see below), whose sum is σ = 21666838242504. Its totient is φ = 18538352755200.

The previous prime is 20101211212111. The next prime is 20101211212151. The reversal of 20101211212121 is 12121211210102.

It can be written as a sum of positive squares in 4 ways, for example, as 256502744521 + 19844708467600 = 506461^2 + 4454740^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20101211212121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20101211212121.

It is not an unprimeable number, because it can be changed into a prime (20101211212111) 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, 692128280 + ... + 692157321.

It is an arithmetic number, because the mean of its divisors is an integer number (2708354780313).

Almost surely, 2^{20101211212121} is an apocalyptic number.

It is an amenable number.

20101211212121 is a deficient number, since it is larger than the sum of its proper divisors (1565627030383).

20101211212121 is a wasteful number, since it uses less digits than its factorization.

20101211212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1384286731.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 20101211212121 its reverse (12121211210102), we get a palindrome (32222422422223).

The spelling of 20101211212121 in words is "twenty trillion, one hundred one billion, two hundred eleven million, two hundred twelve thousand, one hundred twenty-one".