1561000491893 has 2 divisors, whose sum is σ = 1561000491894. Its totient is φ = 1561000491892.

The previous prime is 1561000491851. The next prime is 1561000491907. The reversal of 1561000491893 is 3981940001651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1523392810564 + 37607681329 = 1234258^2 + 193927^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561000491893 - 2²⁴ = 1560983714677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561000491833) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780500245946 + 780500245947.

It is an arithmetic number, because the mean of its divisors is an integer number (780500245947).

Almost surely, 2^{1561000491893} is an apocalyptic number.

It is an amenable number.

1561000491893 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561000491893 is an equidigital number, since it uses as much as digits as its factorization.

1561000491893 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 233280, while the sum is 47.

The spelling of 1561000491893 in words is "one trillion, five hundred sixty-one billion, four hundred ninety-one thousand, eight hundred ninety-three".