161547661 has 16 divisors (see below), whose sum is σ = 187251840. Its totient is φ = 137954880.

The previous prime is 161547641. The next prime is 161547677. The reversal of 161547661 is 166745161.

It is a cyclic number.

It is not a de Polignac number, because 161547661 - 2⁹ = 161547149 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a self number, because there is not a number n which added to its sum of digits gives 161547661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161547611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4960 + ... + 18646.

It is an arithmetic number, because the mean of its divisors is an integer number (11703240).

Almost surely, 2^161547661 is an apocalyptic number.

161547661 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

161547661 is a deficient number, since it is larger than the sum of its proper divisors (25704179).

161547661 is a wasteful number, since it uses less digits than its factorization.

161547661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13764.

The product of its digits is 30240, while the sum is 37.

The square root of 161547661 is about 12710.1400857740. The cubic root of 161547661 is about 544.6283255499.

The spelling of 161547661 in words is "one hundred sixty-one million, five hundred forty-seven thousand, six hundred sixty-one".