561264749261 has 2 divisors, whose sum is σ = 561264749262. Its totient is φ = 561264749260.

The previous prime is 561264749249. The next prime is 561264749263. The reversal of 561264749261 is 162947462165.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 370290505225 + 190974244036 = 608515^2 + 437006^2 .

It is a cyclic number.

It is not a de Polignac number, because 561264749261 - 2⁶ = 561264749197 is a prime.

It is a super-2 number, since 2×561264749261² (a number of 24 digits) contains 22 as substring.

Together with 561264749263, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (561264749263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280632374630 + 280632374631.

It is an arithmetic number, because the mean of its divisors is an integer number (280632374631).

Almost surely, 2^561264749261 is an apocalyptic number.

It is an amenable number.

561264749261 is a deficient number, since it is larger than the sum of its proper divisors (1).

561264749261 is an equidigital number, since it uses as much as digits as its factorization.

561264749261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4354560, while the sum is 53.

The spelling of 561264749261 in words is "five hundred sixty-one billion, two hundred sixty-four million, seven hundred forty-nine thousand, two hundred sixty-one".