15611781113 has 2 divisors, whose sum is σ = 15611781114. Its totient is φ = 15611781112.

The previous prime is 15611781089. The next prime is 15611781121. The reversal of 15611781113 is 31118711651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11372729449 + 4239051664 = 106643^2 + 65108^2 .

It is a cyclic number.

It is not a de Polignac number, because 15611781113 - 2¹⁸ = 15611518969 is a prime.

It is not a weakly prime, because it can be changed into another prime (15611781013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7805890556 + 7805890557.

It is an arithmetic number, because the mean of its divisors is an integer number (7805890557).

Almost surely, 2^15611781113 is an apocalyptic number.

It is an amenable number.

15611781113 is a deficient number, since it is larger than the sum of its proper divisors (1).

15611781113 is an equidigital number, since it uses as much as digits as its factorization.

15611781113 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5040, while the sum is 35.

The spelling of 15611781113 in words is "fifteen billion, six hundred eleven million, seven hundred eighty-one thousand, one hundred thirteen".