203100021 has 16 divisors (see below), whose sum is σ = 311265600. Its totient is φ = 130730544.

The previous prime is 203099999. The next prime is 203100031. The reversal of 203100021 is 120001302.

It is a happy number.

It is not a de Polignac number, because 203100021 - 2⁶ = 203099957 is a prime.

It is a super-3 number, since 3×203100021³ (a number of 26 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 203099976 and 203100012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (203100031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128911 + ... + 130476.

It is an arithmetic number, because the mean of its divisors is an integer number (19454100).

Almost surely, 2^203100021 is an apocalyptic number.

It is an amenable number.

203100021 is a deficient number, since it is larger than the sum of its proper divisors (108165579).

203100021 is a wasteful number, since it uses less digits than its factorization.

203100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259425 (or 259419 counting only the distinct ones).

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

The square root of 203100021 is about 14251.3164655059. The cubic root of 203100021 is about 587.8095749468.

Adding to 203100021 its reverse (120001302), we get a palindrome (323101323).

The spelling of 203100021 in words is "two hundred three million, one hundred thousand, twenty-one".