161606691 has 16 divisors (see below), whose sum is σ = 241745920. Its totient is φ = 106689960.

The previous prime is 161606681. The next prime is 161606719. The reversal of 161606691 is 196606161.

It is not a de Polignac number, because 161606691 - 2¹⁷ = 161475619 is a prime.

It is a super-2 number, since 2×161606691² = 52233445151938962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161606651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26275 + ... + 31836.

It is an arithmetic number, because the mean of its divisors is an integer number (15109120).

Almost surely, 2^161606691 is an apocalyptic number.

161606691 is a deficient number, since it is larger than the sum of its proper divisors (80139229).

161606691 is a wasteful number, since it uses less digits than its factorization.

161606691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58223 (or 58217 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 161606691 is about 12712.4620353415. The cubic root of 161606691 is about 544.6946537464.

The spelling of 161606691 in words is "one hundred sixty-one million, six hundred six thousand, six hundred ninety-one".