20021031 has 6 divisors (see below), whose sum is σ = 28919280. Its totient is φ = 13347348.

The previous prime is 20021021. The next prime is 20021059. The reversal of 20021031 is 13012002.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-20021031 is a prime.

It is a super-2 number, since 2×20021031² = 801683364605922, which contains 22 as substring.

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: 2224559 = 20021031 / (2 + 0 + 0 + 2 + 1 + 0 + 3 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20021021) 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, 1112271 + ... + 1112288.

It is an arithmetic number, because the mean of its divisors is an integer number (4819880).

Almost surely, 2^20021031 is an apocalyptic number.

20021031 is a deficient number, since it is larger than the sum of its proper divisors (8898249).

20021031 is a wasteful number, since it uses less digits than its factorization.

20021031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2224565 (or 2224562 counting only the distinct ones).

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

The square root of 20021031 is about 4474.4866744689. The cubic root of 20021031 is about 271.5368731906.

Adding to 20021031 its reverse (13012002), we get a palindrome (33033033).

The spelling of 20021031 in words is "twenty million, twenty-one thousand, thirty-one".