155556551 has 4 divisors (see below), whose sum is σ = 160920600. Its totient is φ = 150192504.

The previous prime is 155556539. The next prime is 155556559. The reversal of 155556551 is 155655551.

It is a happy number.

155556551 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 155556551 - 2⁶ = 155556487 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 (155556559) 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, 2681981 + ... + 2682038.

It is an arithmetic number, because the mean of its divisors is an integer number (40230150).

Almost surely, 2^155556551 is an apocalyptic number.

155556551 is a deficient number, since it is larger than the sum of its proper divisors (5364049).

155556551 is an equidigital number, since it uses as much as digits as its factorization.

155556551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5364048.

The product of its digits is 93750, while the sum is 38.

The square root of 155556551 is about 12472.2311957404. The cubic root of 155556551 is about 537.8106958714.

The spelling of 155556551 in words is "one hundred fifty-five million, five hundred fifty-six thousand, five hundred fifty-one".