1201555111 has 4 divisors (see below), whose sum is σ = 1202077800. Its totient is φ = 1201032424.

The previous prime is 1201555097. The next prime is 1201555123. The reversal of 1201555111 is 1115551021.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1201555111 - 2¹³ = 1201546919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1201555151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 257881 + ... + 262498.

It is an arithmetic number, because the mean of its divisors is an integer number (300519450).

Almost surely, 2^1201555111 is an apocalyptic number.

1201555111 is a deficient number, since it is larger than the sum of its proper divisors (522689).

1201555111 is an equidigital number, since it uses as much as digits as its factorization.

1201555111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 522688.

The product of its (nonzero) digits is 250, while the sum is 22.

The square root of 1201555111 is about 34663.4549778293. The cubic root of 1201555111 is about 1063.1174132610.

The spelling of 1201555111 in words is "one billion, two hundred one million, five hundred fifty-five thousand, one hundred eleven".