20031021 has 12 divisors (see below), whose sum is σ = 28978560. Its totient is φ = 13333320.

The previous prime is 20030987. The next prime is 20031029. The reversal of 20031021 is 12013002.

It is a happy number.

It is not a de Polignac number, because 20031021 - 2⁶ = 20030957 is a prime.

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

It is a junction number, because it is equal to n+sod(n) for n = 20030994 and 20031012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20031029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6436 + ... + 9026.

It is an arithmetic number, because the mean of its divisors is an integer number (2414880).

Almost surely, 2^20031021 is an apocalyptic number.

It is an amenable number.

20031021 is a deficient number, since it is larger than the sum of its proper divisors (8947539).

20031021 is a wasteful number, since it uses less digits than its factorization.

20031021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3456 (or 3453 counting only the distinct ones).

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

The square root of 20031021 is about 4475.6028644195. The cubic root of 20031021 is about 271.5820290787.

Adding to 20031021 its reverse (12013002), we get a palindrome (32044023).

The spelling of 20031021 in words is "twenty million, thirty-one thousand, twenty-one".