1000203021 has 6 divisors (see below), whose sum is σ = 1444737710. Its totient is φ = 666802008.

The previous prime is 1000202993. The next prime is 1000203049. The reversal of 1000203021 is 1203020001.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1000202993) and next prime (1000203049).

It can be written as a sum of positive squares in only one way, i.e., 975312900 + 24890121 = 31230^2 + 4989^2 .

It is not a de Polignac number, because 1000203021 - 2⁵ = 1000202989 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: 111133669 = 1000203021 / (1 + 0 + 0 + 0 + 2 + 0 + 3 + 0 + 2 + 1).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1000202994 and 1000203012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1000203821) 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, 55566826 + ... + 55566843.

Almost surely, 2^1000203021 is an apocalyptic number.

It is an amenable number.

1000203021 is a deficient number, since it is larger than the sum of its proper divisors (444534689).

1000203021 is a wasteful number, since it uses less digits than its factorization.

1000203021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111133675 (or 111133672 counting only the distinct ones).

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

The square root of 1000203021 is about 31625.9864826380. The cubic root of 1000203021 is about 1000.0676690875.

Adding to 1000203021 its reverse (1203020001), we get a palindrome (2203223022).

It can be divided in two parts, 100020 and 3021, that added together give a square (103041 = 321²).

The spelling of 1000203021 in words is "one billion, two hundred three thousand, twenty-one".