161651011 has 4 divisors (see below), whose sum is σ = 171159912. Its totient is φ = 152142112.

The previous prime is 161651003. The next prime is 161651029. The reversal of 161651011 is 110156161.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 110156161 = 151 ⋅729511.

It is not a de Polignac number, because 161651011 - 2³ = 161651003 is a prime.

It is a super-3 number, since 3×161651011³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161651111) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4754425 + ... + 4754458.

It is an arithmetic number, because the mean of its divisors is an integer number (42789978).

Almost surely, 2^161651011 is an apocalyptic number.

161651011 is a deficient number, since it is larger than the sum of its proper divisors (9508901).

161651011 is an equidigital number, since it uses as much as digits as its factorization.

161651011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9508900.

The product of its (nonzero) digits is 180, while the sum is 22.

The square root of 161651011 is about 12714.2050872243. The cubic root of 161651011 is about 544.7444426514.

The spelling of 161651011 in words is "one hundred sixty-one million, six hundred fifty-one thousand, eleven".