1218725205221 has 8 divisors (see below), whose sum is σ = 1219815782400. Its totient is φ = 1217634845760.

The previous prime is 1218725205163. The next prime is 1218725205241. The reversal of 1218725205221 is 1225025278121.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1218725205221 - 2¹⁰ = 1218725204197 is a prime.

It is a super-2 number, since 2×1218725205221² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1218725205241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12407261 + ... + 12505101.

It is an arithmetic number, because the mean of its divisors is an integer number (152476972800).

Almost surely, 2^{1218725205221} is an apocalyptic number.

It is an amenable number.

1218725205221 is a deficient number, since it is larger than the sum of its proper divisors (1090577179).

1218725205221 is an equidigital number, since it uses as much as digits as its factorization.

1218725205221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108859.

The product of its (nonzero) digits is 44800, while the sum is 38.

The spelling of 1218725205221 in words is "one trillion, two hundred eighteen billion, seven hundred twenty-five million, two hundred five thousand, two hundred twenty-one".