20621331 has 8 divisors (see below), whose sum is σ = 30550160. Its totient is φ = 13747536.

The previous prime is 20621329. The next prime is 20621333. The reversal of 20621331 is 13312602.

It is an interprime number because it is at equal distance from previous prime (20621329) and next prime (20621333).

It is not a de Polignac number, because 20621331 - 2¹ = 20621329 is a prime.

It is a super-2 number, since 2×20621331² = 850478584423122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20621333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 381850 + ... + 381903.

It is an arithmetic number, because the mean of its divisors is an integer number (3818770).

Almost surely, 2^20621331 is an apocalyptic number.

20621331 is a deficient number, since it is larger than the sum of its proper divisors (9928829).

20621331 is an equidigital number, since it uses as much as digits as its factorization.

20621331 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 763762 (or 763756 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 20621331 is about 4541.0715695747. The cubic root of 20621331 is about 274.2240650369.

Adding to 20621331 its reverse (13312602), we get a palindrome (33933933).

The spelling of 20621331 in words is "twenty million, six hundred twenty-one thousand, three hundred thirty-one".