161581057787 has 2 divisors, whose sum is σ = 161581057788. Its totient is φ = 161581057786.

The previous prime is 161581057783. The next prime is 161581057789. The reversal of 161581057787 is 787750185161.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 161581057787 - 2² = 161581057783 is a prime.

It is a super-2 number, since 2×161581057787² (a number of 23 digits) contains 22 as substring.

Together with 161581057789, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (161581057783) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80790528893 + 80790528894.

It is an arithmetic number, because the mean of its divisors is an integer number (80790528894).

Almost surely, 2^161581057787 is an apocalyptic number.

161581057787 is a deficient number, since it is larger than the sum of its proper divisors (1).

161581057787 is an equidigital number, since it uses as much as digits as its factorization.

161581057787 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3292800, while the sum is 56.

The spelling of 161581057787 in words is "one hundred sixty-one billion, five hundred eighty-one million, fifty-seven thousand, seven hundred eighty-seven".