21004144001 has 4 divisors (see below), whose sum is σ = 21125555412. Its totient is φ = 20882732592.

The previous prime is 21004143991. The next prime is 21004144009. The reversal of 21004144001 is 10044140012.

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 20317651600 + 686492401 = 142540^2 + 26201^2 .

It is a cyclic number.

It is not a de Polignac number, because 21004144001 - 2¹⁰ = 21004142977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21004144009) 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, 60705446 + ... + 60705791.

It is an arithmetic number, because the mean of its divisors is an integer number (5281388853).

Almost surely, 2^21004144001 is an apocalyptic number.

It is an amenable number.

21004144001 is a deficient number, since it is larger than the sum of its proper divisors (121411411).

21004144001 is a wasteful number, since it uses less digits than its factorization.

21004144001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121411410.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21004144001 its reverse (10044140012), we get a palindrome (31048284013).

The spelling of 21004144001 in words is "twenty-one billion, four million, one hundred forty-four thousand, one".