161864641 has 4 divisors (see below), whose sum is σ = 162631984. Its totient is φ = 161097300.

The previous prime is 161864623. The next prime is 161864653. The reversal of 161864641 is 146468161.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161864641 is a prime.

It is a super-5 number, since 5×161864641⁵ (a number of 42 digits) contains 55555 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161864641.

It is not an unprimeable number, because it can be changed into a prime (161864621) 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, 383355 + ... + 383776.

It is an arithmetic number, because the mean of its divisors is an integer number (40657996).

Almost surely, 2^161864641 is an apocalyptic number.

It is an amenable number.

161864641 is a deficient number, since it is larger than the sum of its proper divisors (767343).

161864641 is an equidigital number, since it uses as much as digits as its factorization.

161864641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 767342.

The product of its digits is 27648, while the sum is 37.

The square root of 161864641 is about 12722.6035464444. The cubic root of 161864641 is about 544.9843061440.

The spelling of 161864641 in words is "one hundred sixty-one million, eight hundred sixty-four thousand, six hundred forty-one".