561551815 has 8 divisors (see below), whose sum is σ = 735122448. Its totient is φ = 408401280.

The previous prime is 561551807. The next prime is 561551839. The reversal of 561551815 is 518155165.

It is a happy number.

561551815 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is not a de Polignac number, because 561551815 - 2³ = 561551807 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5104962 + ... + 5105071.

It is an arithmetic number, because the mean of its divisors is an integer number (91890306).

Almost surely, 2^561551815 is an apocalyptic number.

561551815 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

561551815 is a deficient number, since it is larger than the sum of its proper divisors (173570633).

561551815 is a wasteful number, since it uses less digits than its factorization.

561551815 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10210049.

The product of its digits is 30000, while the sum is 37.

The square root of 561551815 is about 23697.0845253166. The cubic root of 561551815 is about 825.0177235250.

It can be divided in two parts, 56155 and 1815, that added together give a triangular number (57970 = T₃₄₀).

The spelling of 561551815 in words is "five hundred sixty-one million, five hundred fifty-one thousand, eight hundred fifteen".