131121555 has 8 divisors (see below), whose sum is σ = 209794512. Its totient is φ = 69931488.

The previous prime is 131121539. The next prime is 131121559. The reversal of 131121555 is 555121131.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 131121555 - 2⁴ = 131121539 is a prime.

It is not an unprimeable number, because it can be changed into a prime (131121559) 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 in 7 ways as a sum of consecutive naturals, for example, 4370704 + ... + 4370733.

It is an arithmetic number, because the mean of its divisors is an integer number (26224314).

Almost surely, 2^131121555 is an apocalyptic number.

131121555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

131121555 is a deficient number, since it is larger than the sum of its proper divisors (78672957).

131121555 is an equidigital number, since it uses as much as digits as its factorization.

131121555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8741445.

The product of its digits is 750, while the sum is 24.

The square root of 131121555 is about 11450.8320658370. The cubic root of 131121555 is about 508.0323452135.

Adding to 131121555 its reverse (555121131), we get a palindrome (686242686).

The spelling of 131121555 in words is "one hundred thirty-one million, one hundred twenty-one thousand, five hundred fifty-five".