561381555 has 32 divisors (see below), whose sum is σ = 1050407424. Its totient is φ = 250661376.

The previous prime is 561381551. The next prime is 561381571. The reversal of 561381555 is 555183165.

It is not a de Polignac number, because 561381555 - 2² = 561381551 is a prime.

It is not an unprimeable number, because it can be changed into a prime (561381551) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 57654 + ... + 66683.

It is an arithmetic number, because the mean of its divisors is an integer number (32825232).

Almost surely, 2^561381555 is an apocalyptic number.

561381555 is a deficient number, since it is larger than the sum of its proper divisors (489025869).

561381555 is a wasteful number, since it uses less digits than its factorization.

561381555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124395.

The product of its digits is 90000, while the sum is 39.

The square root of 561381555 is about 23693.4918279261. The cubic root of 561381555 is about 824.9343345348.

The spelling of 561381555 in words is "five hundred sixty-one million, three hundred eighty-one thousand, five hundred fifty-five".