523212121 has 4 divisors (see below), whose sum is σ = 523286244. Its totient is φ = 523138000.

The previous prime is 523212091. The next prime is 523212127. The reversal of 523212121 is 121212325.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 386672896 + 136539225 = 19664^2 + 11685^2 .

It is a cyclic number.

It is not a de Polignac number, because 523212121 - 2²¹ = 521114969 is a prime.

It is a super-2 number, since 2×523212121² = 547501847122637282, which contains 22 as substring.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (523212127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25210 + ... + 41011.

It is an arithmetic number, because the mean of its divisors is an integer number (130821561).

Almost surely, 2^523212121 is an apocalyptic number.

It is an amenable number.

523212121 is a deficient number, since it is larger than the sum of its proper divisors (74123).

523212121 is an equidigital number, since it uses as much as digits as its factorization.

523212121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74122.

The product of its digits is 240, while the sum is 19.

The square root of 523212121 is about 22873.8304837646. The cubic root of 523212121 is about 805.7975306609.

Adding to 523212121 its reverse (121212325), we get a palindrome (644424446).

The spelling of 523212121 in words is "five hundred twenty-three million, two hundred twelve thousand, one hundred twenty-one".