161864643 has 8 divisors (see below), whose sum is σ = 215894800. Its totient is φ = 107872128.

The previous prime is 161864623. The next prime is 161864653. The reversal of 161864643 is 346468161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161864643 - 2⁸ = 161864387 is a prime.

It is a super-5 number, since 5×161864643⁵ (a number of 42 digits) contains 55555 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161864623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2943 + ... + 18231.

It is an arithmetic number, because the mean of its divisors is an integer number (26986850).

Almost surely, 2^161864643 is an apocalyptic number.

161864643 is a deficient number, since it is larger than the sum of its proper divisors (54030157).

161864643 is a wasteful number, since it uses less digits than its factorization.

161864643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18821.

The product of its digits is 82944, while the sum is 39.

The square root of 161864643 is about 12722.6036250447. The cubic root of 161864643 is about 544.9843083887.

The spelling of 161864643 in words is "one hundred sixty-one million, eight hundred sixty-four thousand, six hundred forty-three".