21043402001 has 4 divisors (see below), whose sum is σ = 21044564004. Its totient is φ = 21042240000.

The previous prime is 21043401923. The next prime is 21043402019. The reversal of 21043402001 is 10020434012.

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 13286020225 + 7757381776 = 115265^2 + 88076^2 .

It is a cyclic number.

It is not a de Polignac number, because 21043402001 - 2¹⁴ = 21043385617 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21043402021) 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, 553400 + ... + 590201.

It is an arithmetic number, because the mean of its divisors is an integer number (5261141001).

Almost surely, 2^21043402001 is an apocalyptic number.

It is an amenable number.

21043402001 is a deficient number, since it is larger than the sum of its proper divisors (1162003).

21043402001 is a wasteful number, since it uses less digits than its factorization.

21043402001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1162002.

The product of its (nonzero) digits is 192, while the sum is 17.

Adding to 21043402001 its reverse (10020434012), we get a palindrome (31063836013).

The spelling of 21043402001 in words is "twenty-one billion, forty-three million, four hundred two thousand, one".