1221354187 has 2 divisors, whose sum is σ = 1221354188. Its totient is φ = 1221354186.

The previous prime is 1221354163. The next prime is 1221354263. The reversal of 1221354187 is 7814531221.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221354187 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221354107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610677093 + 610677094.

It is an arithmetic number, because the mean of its divisors is an integer number (610677094).

Almost surely, 2^1221354187 is an apocalyptic number.

1221354187 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221354187 is an equidigital number, since it uses as much as digits as its factorization.

1221354187 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 34.

The square root of 1221354187 is about 34947.8781473210. The cubic root of 1221354187 is about 1068.9249361649.

The spelling of 1221354187 in words is "one billion, two hundred twenty-one million, three hundred fifty-four thousand, one hundred eighty-seven".