20212531 has 2 divisors, whose sum is σ = 20212532. Its totient is φ = 20212530.

The previous prime is 20212529. The next prime is 20212547. The reversal of 20212531 is 13521202.

It is an a-pointer prime, because the next prime (20212547) can be obtained adding 20212531 to its sum of digits (16).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20212531 - 2¹ = 20212529 is a prime.

It is a super-2 number, since 2×20212531² = 817092818851922, which contains 22 as substring.

Together with 20212529, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20212831) 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 as a sum of consecutive naturals, namely, 10106265 + 10106266.

It is an arithmetic number, because the mean of its divisors is an integer number (10106266).

Almost surely, 2^20212531 is an apocalyptic number.

20212531 is a deficient number, since it is larger than the sum of its proper divisors (1).

20212531 is an equidigital number, since it uses as much as digits as its factorization.

20212531 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 20212531 is about 4495.8348501697. The cubic root of 20212531 is about 272.3998723120.

Adding to 20212531 its reverse (13521202), we get a palindrome (33733733).

The spelling of 20212531 in words is "twenty million, two hundred twelve thousand, five hundred thirty-one".