21001203001 has 4 divisors (see below), whose sum is σ = 21122597412. Its totient is φ = 20879808592.

The previous prime is 21001202993. The next prime is 21001203007. The reversal of 21001203001 is 10030210012.

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 16724696976 + 4276506025 = 129324^2 + 65395^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001203001 - 2³ = 21001202993 is a prime.

It is a super-2 number, since 2×21001203001² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21001203007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 60696946 + ... + 60697291.

It is an arithmetic number, because the mean of its divisors is an integer number (5280649353).

Almost surely, 2^21001203001 is an apocalyptic number.

It is an amenable number.

21001203001 is a deficient number, since it is larger than the sum of its proper divisors (121394411).

21001203001 is a wasteful number, since it uses less digits than its factorization.

21001203001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121394410.

The product of its (nonzero) digits is 12, while the sum is 10.

Adding to 21001203001 its reverse (10030210012), we get a palindrome (31031413013).

The spelling of 21001203001 in words is "twenty-one billion, one million, two hundred three thousand, one".