161491787 has 2 divisors, whose sum is σ = 161491788. Its totient is φ = 161491786.

The previous prime is 161491777. The next prime is 161491801. The reversal of 161491787 is 787194161.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 161491787 - 2¹² = 161487691 is a prime.

It is not a weakly prime, because it can be changed into another prime (161491727) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80745893 + 80745894.

It is an arithmetic number, because the mean of its divisors is an integer number (80745894).

Almost surely, 2^161491787 is an apocalyptic number.

161491787 is a deficient number, since it is larger than the sum of its proper divisors (1).

161491787 is an equidigital number, since it uses as much as digits as its factorization.

161491787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 84672, while the sum is 44.

The square root of 161491787 is about 12707.9418868674. The cubic root of 161491787 is about 544.5655286600.

The spelling of 161491787 in words is "one hundred sixty-one million, four hundred ninety-one thousand, seven hundred eighty-seven".