531821606121 has 135 divisors (see below), whose sum is σ = 902621508327. Its totient is φ = 311890344480.

The previous prime is 531821606089. The next prime is 531821606137. The reversal of 531821606121 is 121606128135.

The square root of 531821606121 is 729261.

It is a perfect power (a square), and thus also a powerful number.

531821606121 is a `hidden beast` number, since 5 + 3 + 1 + 8 + 21 + 606 + 1 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 78671835225 + 453149770896 = 280485^2 + 673164^2 .

It is not a de Polignac number, because 531821606121 - 2⁵ = 531821606089 is a prime.

It is not an unprimeable number, because it can be changed into a prime (531821606161) by changing a digit.

It is a polite number, since it can be written in 134 ways as a sum of consecutive naturals, for example, 1962441216 + ... + 1962441486.

Almost surely, 2^531821606121 is an apocalyptic number.

531821606121 is the 729261-st square number.

531821606121 is the 364631-st centered octagonal number.

It is an amenable number.

531821606121 is a deficient number, since it is larger than the sum of its proper divisors (370799902206).

531821606121 is an equidigital number, since it uses as much as digits as its factorization.

531821606121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626 (or 310 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 36.

Multiplying 531821606121 by its sum of digits (36), we get a square (19145577820356 = 4375566²).

The spelling of 531821606121 in words is "five hundred thirty-one billion, eight hundred twenty-one million, six hundred six thousand, one hundred twenty-one".