120405551 has 4 divisors (see below), whose sum is σ = 137606352. Its totient is φ = 103204752.

The previous prime is 120405541. The next prime is 120405557. The reversal of 120405551 is 155504021.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 155504021 = 41 ⋅3792781.

It is not a de Polignac number, because 120405551 - 2⁶ = 120405487 is a prime.

It is a super-2 number, since 2×120405551² = 28994993423227202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (120405557) 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, 8600390 + ... + 8600403.

It is an arithmetic number, because the mean of its divisors is an integer number (34401588).

Almost surely, 2^120405551 is an apocalyptic number.

120405551 is a deficient number, since it is larger than the sum of its proper divisors (17200801).

120405551 is an equidigital number, since it uses as much as digits as its factorization.

120405551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17200800.

The product of its (nonzero) digits is 1000, while the sum is 23.

The square root of 120405551 is about 10972.9463226610. The cubic root of 120405551 is about 493.7974427307.

Adding to 120405551 its reverse (155504021), we get a palindrome (275909572).

The spelling of 120405551 in words is "one hundred twenty million, four hundred five thousand, five hundred fifty-one".