122155591 has 4 divisors (see below), whose sum is σ = 129341232. Its totient is φ = 114969952.

The previous prime is 122155589. The next prime is 122155597. The reversal of 122155591 is 195551221.

It is a happy number.

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 122155591 - 2¹ = 122155589 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 (122155597) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3592795 + ... + 3592828.

It is an arithmetic number, because the mean of its divisors is an integer number (32335308).

Almost surely, 2^122155591 is an apocalyptic number.

122155591 is a deficient number, since it is larger than the sum of its proper divisors (7185641).

122155591 is an equidigital number, since it uses as much as digits as its factorization.

122155591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7185640.

The product of its digits is 4500, while the sum is 31.

The square root of 122155591 is about 11052.4020466141. The cubic root of 122155591 is about 496.1783185912.

It can be divided in two parts, 1221555 and 91, that multiplied together give a triangular number (111161505 = T₁₄₉₁₀).

The spelling of 122155591 in words is "one hundred twenty-two million, one hundred fifty-five thousand, five hundred ninety-one".