1555225551 has 24 divisors (see below), whose sum is σ = 2516898384. Its totient is φ = 917084160.

The previous prime is 1555225537. The next prime is 1555225583.

1555225551 is a `hidden beast` number, since 1 + 5 + 552 + 2 + 55 + 51 = 666.

1555225551 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1555225551 - 2⁵ = 1555225519 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1555225751) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 208626 + ... + 215951.

It is an arithmetic number, because the mean of its divisors is an integer number (104870766).

Almost surely, 2^1555225551 is an apocalyptic number.

1555225551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1555225551 is a deficient number, since it is larger than the sum of its proper divisors (961672833).

1555225551 is a wasteful number, since it uses less digits than its factorization.

1555225551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424631 (or 424628 counting only the distinct ones).

The product of its digits is 62500, while the sum is 36.

The square root of 1555225551 is about 39436.3480941124. The cubic root of 1555225551 is about 1158.5936064558.

The spelling of 1555225551 in words is "one billion, five hundred fifty-five million, two hundred twenty-five thousand, five hundred fifty-one".