612166221 has 32 divisors (see below), whose sum is σ = 933851520. Its totient is φ = 396047232.

The previous prime is 612166213. The next prime is 612166237. The reversal of 612166221 is 122661216.

It is not a de Polignac number, because 612166221 - 2³ = 612166213 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (612166421) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 641881 + ... + 642833.

It is an arithmetic number, because the mean of its divisors is an integer number (29182860).

Almost surely, 2^612166221 is an apocalyptic number.

It is an amenable number.

612166221 is a deficient number, since it is larger than the sum of its proper divisors (321685299).

612166221 is a wasteful number, since it uses less digits than its factorization.

612166221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1642 (or 1636 counting only the distinct ones).

The product of its digits is 1728, while the sum is 27.

The square root of 612166221 is about 24741.9930684656. The cubic root of 612166221 is about 849.0953332246.

The spelling of 612166221 in words is "six hundred twelve million, one hundred sixty-six thousand, two hundred twenty-one".