531581021 has 2 divisors, whose sum is σ = 531581022. Its totient is φ = 531581020.

The previous prime is 531581009. The next prime is 531581033. The reversal of 531581021 is 120185135.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (531581009) and next prime (531581033).

It can be written as a sum of positive squares in only one way, i.e., 523768996 + 7812025 = 22886^2 + 2795^2 .

It is a cyclic number.

It is not a de Polignac number, because 531581021 - 2¹⁴ = 531564637 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (531581051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 265790510 + 265790511.

It is an arithmetic number, because the mean of its divisors is an integer number (265790511).

Almost surely, 2^531581021 is an apocalyptic number.

It is an amenable number.

531581021 is a deficient number, since it is larger than the sum of its proper divisors (1).

531581021 is an equidigital number, since it uses as much as digits as its factorization.

531581021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1200, while the sum is 26.

The square root of 531581021 is about 23056.0408786938. The cubic root of 531581021 is about 810.0711317911.

The spelling of 531581021 in words is "five hundred thirty-one million, five hundred eighty-one thousand, twenty-one".