154917221 has 2 divisors, whose sum is σ = 154917222. Its totient is φ = 154917220.

The previous prime is 154917193. The next prime is 154917223. The reversal of 154917221 is 122719451.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 154132225 + 784996 = 12415^2 + 886^2 .

It is a cyclic number.

It is not a de Polignac number, because 154917221 - 2¹⁰ = 154916197 is a prime.

Together with 154917223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (154917223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77458610 + 77458611.

It is an arithmetic number, because the mean of its divisors is an integer number (77458611).

Almost surely, 2^154917221 is an apocalyptic number.

It is an amenable number.

154917221 is a deficient number, since it is larger than the sum of its proper divisors (1).

154917221 is an equidigital number, since it uses as much as digits as its factorization.

154917221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 32.

The square root of 154917221 is about 12446.5746693618. The cubic root of 154917221 is about 537.0728920700.

The spelling of 154917221 in words is "one hundred fifty-four million, nine hundred seventeen thousand, two hundred twenty-one".