561111100551 has 16 divisors (see below), whose sum is σ = 839506161120. Its totient is φ = 370370361600.

The previous prime is 561111100547. The next prime is 561111100567. The reversal of 561111100551 is 155001111165.

561111100551 is a `hidden beast` number, since 5 + 6 + 1 + 1 + 1 + 1 + 100 + 551 = 666.

It is not a de Polignac number, because 561111100551 - 2² = 561111100547 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561111107551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 102877930 + ... + 102883383.

It is an arithmetic number, because the mean of its divisors is an integer number (52469135070).

Almost surely, 2^561111100551 is an apocalyptic number.

561111100551 is a deficient number, since it is larger than the sum of its proper divisors (278395060569).

561111100551 is a wasteful number, since it uses less digits than its factorization.

561111100551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 205761423 (or 205761417 counting only the distinct ones).

The product of its (nonzero) digits is 750, while the sum is 27.

The spelling of 561111100551 in words is "five hundred sixty-one billion, one hundred eleven million, one hundred thousand, five hundred fifty-one".