21042001001 has 4 divisors (see below), whose sum is σ = 24048001152. Its totient is φ = 18036000852.

The previous prime is 21042000911. The next prime is 21042001009. The reversal of 21042001001 is 10010024012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21042001001 is a prime.

It is a super-2 number, since 2×21042001001² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21042001009) 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, 1503000065 + ... + 1503000078.

It is an arithmetic number, because the mean of its divisors is an integer number (6012000288).

Almost surely, 2^21042001001 is an apocalyptic number.

It is an amenable number.

21042001001 is a deficient number, since it is larger than the sum of its proper divisors (3006000151).

21042001001 is an equidigital number, since it uses as much as digits as its factorization.

21042001001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3006000150.

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21042001001 its reverse (10010024012), we get a palindrome (31052025013).

The spelling of 21042001001 in words is "twenty-one billion, forty-two million, one thousand, one".