154191221 has 2 divisors, whose sum is σ = 154191222. Its totient is φ = 154191220.

The previous prime is 154191211. The next prime is 154191239. The reversal of 154191221 is 122191451.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 97022500 + 57168721 = 9850^2 + 7561^2 .

It is a cyclic number.

It is not a de Polignac number, because 154191221 - 2⁶ = 154191157 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (154191211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77095610 + 77095611.

It is an arithmetic number, because the mean of its divisors is an integer number (77095611).

Almost surely, 2^154191221 is an apocalyptic number.

It is an amenable number.

154191221 is a deficient number, since it is larger than the sum of its proper divisors (1).

154191221 is an equidigital number, since it uses as much as digits as its factorization.

154191221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 720, while the sum is 26.

The square root of 154191221 is about 12417.3757694611. The cubic root of 154191221 is about 536.2326032938.

The spelling of 154191221 in words is "one hundred fifty-four million, one hundred ninety-one thousand, two hundred twenty-one".