618071221 has 4 divisors (see below), whose sum is σ = 622219500. Its totient is φ = 613922944.

The previous prime is 618071191. The next prime is 618071239. The reversal of 618071221 is 122170816.

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 172396900 + 445674321 = 13130^2 + 21111^2 .

It is a cyclic number.

It is not a de Polignac number, because 618071221 - 2⁹ = 618070709 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 618071221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (618071821) 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, 2073916 + ... + 2074213.

It is an arithmetic number, because the mean of its divisors is an integer number (155554875).

Almost surely, 2^618071221 is an apocalyptic number.

It is an amenable number.

618071221 is a deficient number, since it is larger than the sum of its proper divisors (4148279).

618071221 is a wasteful number, since it uses less digits than its factorization.

618071221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4148278.

The product of its (nonzero) digits is 1344, while the sum is 28.

The square root of 618071221 is about 24861.0382124319. The cubic root of 618071221 is about 851.8167467375.

The spelling of 618071221 in words is "six hundred eighteen million, seventy-one thousand, two hundred twenty-one".