20531021 has 8 divisors (see below), whose sum is σ = 24221184. Its totient is φ = 17030160.

The previous prime is 20530987. The next prime is 20531023. The reversal of 20531021 is 12013502.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 20531021 - 2²² = 16336717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20530987 and 20531005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20531023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47090 + ... + 47523.

It is an arithmetic number, because the mean of its divisors is an integer number (3027648).

Almost surely, 2^20531021 is an apocalyptic number.

It is an amenable number.

20531021 is a deficient number, since it is larger than the sum of its proper divisors (3690163).

20531021 is an equidigital number, since it uses as much as digits as its factorization.

20531021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94651.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 20531021 is about 4531.1169704610. The cubic root of 20531021 is about 273.8231627525.

Adding to 20531021 its reverse (12013502), we get a palindrome (32544523).

The spelling of 20531021 in words is "twenty million, five hundred thirty-one thousand, twenty-one".