561381551 has 2 divisors, whose sum is σ = 561381552. Its totient is φ = 561381550.

The previous prime is 561381523. The next prime is 561381571. The reversal of 561381551 is 155183165.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 561381551 - 2¹⁸ = 561119407 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561381521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280690775 + 280690776.

It is an arithmetic number, because the mean of its divisors is an integer number (280690776).

Almost surely, 2^561381551 is an apocalyptic number.

561381551 is a deficient number, since it is larger than the sum of its proper divisors (1).

561381551 is an equidigital number, since it uses as much as digits as its factorization.

561381551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18000, while the sum is 35.

The square root of 561381551 is about 23693.4917435147. The cubic root of 561381551 is about 824.9343325755.

The spelling of 561381551 in words is "five hundred sixty-one million, three hundred eighty-one thousand, five hundred fifty-one".