161651647 has 4 divisors (see below), whose sum is σ = 164301736. Its totient is φ = 159001560.

The previous prime is 161651627. The next prime is 161651669. The reversal of 161651647 is 746156161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 746156161 = 47 ⋅15875663.

It is a cyclic number.

It is not a de Polignac number, because 161651647 - 2⁷ = 161651519 is a prime.

It is a super-2 number, since 2×161651647² = 52262509955625218, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161651627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1324953 + ... + 1325074.

It is an arithmetic number, because the mean of its divisors is an integer number (41075434).

Almost surely, 2^161651647 is an apocalyptic number.

161651647 is a deficient number, since it is larger than the sum of its proper divisors (2650089).

161651647 is an equidigital number, since it uses as much as digits as its factorization.

161651647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2650088.

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

The square root of 161651647 is about 12714.2300985943. The cubic root of 161651647 is about 544.7451570649.

The spelling of 161651647 in words is "one hundred sixty-one million, six hundred fifty-one thousand, six hundred forty-seven".