20121021001 has 2 divisors, whose sum is σ = 20121021002. Its totient is φ = 20121021000.

The previous prime is 20121020999. The next prime is 20121021031. The reversal of 20121021001 is 10012012102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12611065401 + 7509955600 = 112299^2 + 86660^2 .

It is a cyclic number.

It is not a de Polignac number, because 20121021001 - 2¹ = 20121020999 is a prime.

It is a super-2 number, since 2×20121021001² (a number of 21 digits) contains 22 as substring.

Together with 20121020999, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20121021031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10060510500 + 10060510501.

It is an arithmetic number, because the mean of its divisors is an integer number (10060510501).

Almost surely, 2^20121021001 is an apocalyptic number.

It is an amenable number.

20121021001 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121021001 is an equidigital number, since it uses as much as digits as its factorization.

20121021001 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 20121021001 its reverse (10012012102), we get a palindrome (30133033103).

It can be divided in two parts, 2012102 and 1001, that multiplied together give a palindrome (2014114102).

The spelling of 20121021001 in words is "twenty billion, one hundred twenty-one million, twenty-one thousand, one".