21203000001 has 6 divisors (see below), whose sum is σ = 30626555570. Its totient is φ = 14135333328.

The previous prime is 21202999969. The next prime is 21203000003. The reversal of 21203000001 is 10000030212.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 20128799376 + 1074200625 = 141876^2 + 32775^2 .

It is not a de Polignac number, because 21203000001 - 2⁵ = 21202999969 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 2355888889 = 21203000001 / (2 + 1 + 2 + 0 + 3 + 0 + 0 + 0 + 0 + 0 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21203000003) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1177944436 + ... + 1177944453.

Almost surely, 2^21203000001 is an apocalyptic number.

It is an amenable number.

21203000001 is a deficient number, since it is larger than the sum of its proper divisors (9423555569).

21203000001 is a wasteful number, since it uses less digits than its factorization.

21203000001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2355888895 (or 2355888892 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

Adding to 21203000001 its reverse (10000030212), we get a palindrome (31203030213).

The spelling of 21203000001 in words is "twenty-one billion, two hundred three million, one", and thus it is an aban number.