21000012000001 has 4 divisors (see below), whose sum is σ = 21017497440004. Its totient is φ = 20982526560000.

The previous prime is 21000011999969. The next prime is 21000012000007. The reversal of 21000012000001 is 10000021000012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5863056890625 + 15136955109376 = 2421375^2 + 3890624^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000012000001 - 2⁵ = 21000011999969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21000012000007) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8742718200 + ... + 8742720601.

It is an arithmetic number, because the mean of its divisors is an integer number (5254374360001).

Almost surely, 2^{21000012000001} is an apocalyptic number.

It is an amenable number.

21000012000001 is a deficient number, since it is larger than the sum of its proper divisors (17485440003).

21000012000001 is a wasteful number, since it uses less digits than its factorization.

21000012000001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17485440002.

The product of its (nonzero) digits is 4, while the sum is 7.

Adding to 21000012000001 its reverse (10000021000012), we get a palindrome (31000033000013).

The spelling of 21000012000001 in words is "twenty-one trillion, twelve million, one", and thus it is an aban number and an uban number.