131224021 has 2 divisors, whose sum is σ = 131224022. Its totient is φ = 131224020.

The previous prime is 131224007. The next prime is 131224057. The reversal of 131224021 is 120422131.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 130644900 + 579121 = 11430^2 + 761^2 .

It is a cyclic number.

It is not a de Polignac number, because 131224021 - 2¹⁵ = 131191253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 131223986 and 131224004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131224061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 65612010 + 65612011.

It is an arithmetic number, because the mean of its divisors is an integer number (65612011).

Almost surely, 2^131224021 is an apocalyptic number.

It is an amenable number.

131224021 is a deficient number, since it is larger than the sum of its proper divisors (1).

131224021 is an equidigital number, since it uses as much as digits as its factorization.

131224021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 16.

The square root of 131224021 is about 11455.3053647644. The cubic root of 131224021 is about 508.1646460858.

Adding to 131224021 its reverse (120422131), we get a palindrome (251646152).

The spelling of 131224021 in words is "one hundred thirty-one million, two hundred twenty-four thousand, twenty-one".