155665201 has 2 divisors, whose sum is σ = 155665202. Its totient is φ = 155665200.

The previous prime is 155665199. The next prime is 155665207. The reversal of 155665201 is 102566551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 109411600 + 46253601 = 10460^2 + 6801^2 .

It is a cyclic number.

It is not a de Polignac number, because 155665201 - 2¹ = 155665199 is a prime.

Together with 155665199, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (155665207) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77832600 + 77832601.

It is an arithmetic number, because the mean of its divisors is an integer number (77832601).

Almost surely, 2^155665201 is an apocalyptic number.

It is an amenable number.

155665201 is a deficient number, since it is larger than the sum of its proper divisors (1).

155665201 is an equidigital number, since it uses as much as digits as its factorization.

155665201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9000, while the sum is 31.

The square root of 155665201 is about 12476.5861115932. The cubic root of 155665201 is about 537.9358797838.

The spelling of 155665201 in words is "one hundred fifty-five million, six hundred sixty-five thousand, two hundred one".