161868861 has 96 divisors (see below), whose sum is σ = 311141376. Its totient is φ = 81648000.

The previous prime is 161868803. The next prime is 161868869. The reversal of 161868861 is 168868161.

It is not a de Polignac number, because 161868861 - 2⁶ = 161868797 is a prime.

It is a super-2 number, since 2×161868861² = 52403056322874642, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161868869) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 767046 + ... + 767256.

It is an arithmetic number, because the mean of its divisors is an integer number (3241056).

Almost surely, 2^161868861 is an apocalyptic number.

161868861 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

161868861 is a deficient number, since it is larger than the sum of its proper divisors (149272515).

161868861 is a wasteful number, since it uses less digits than its factorization.

161868861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 285 (or 273 counting only the distinct ones).

The product of its digits is 110592, while the sum is 45.

The square root of 161868861 is about 12722.7693919209. The cubic root of 161868861 is about 544.9890422284.

The spelling of 161868861 in words is "one hundred sixty-one million, eight hundred sixty-eight thousand, eight hundred sixty-one".