612121221 has 24 divisors (see below), whose sum is σ = 903684600. Its totient is φ = 399125376.

The previous prime is 612121201. The next prime is 612121231. The reversal of 612121221 is 122121216.

It can be written as a sum of positive squares in 4 ways, for example, as 308002500 + 304118721 = 17550^2 + 17439^2 .

It is not a de Polignac number, because 612121221 - 2⁵ = 612121189 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 612121194 and 612121203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (612121201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 164635 + ... + 168311.

It is an arithmetic number, because the mean of its divisors is an integer number (37653525).

Almost surely, 2^612121221 is an apocalyptic number.

It is an amenable number.

612121221 is a deficient number, since it is larger than the sum of its proper divisors (291563379).

612121221 is a wasteful number, since it uses less digits than its factorization.

612121221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4085 (or 4082 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 612121221 is about 24741.0836666465. The cubic root of 612121221 is about 849.0745272055.

Adding to 612121221 its reverse (122121216), we get a palindrome (734242437).

The spelling of 612121221 in words is "six hundred twelve million, one hundred twenty-one thousand, two hundred twenty-one".