161816640 has 56 divisors (see below), whose sum is σ = 513770880. Its totient is φ = 43150848.

The previous prime is 161816617. The next prime is 161816647. The reversal of 161816640 is 46618161.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161816647) 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, 83320 + ... + 85239.

It is an arithmetic number, because the mean of its divisors is an integer number (9174480).

Almost surely, 2^161816640 is an apocalyptic number.

161816640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161816640 is an abundant number, since it is smaller than the sum of its proper divisors (351954240).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161816640 is a wasteful number, since it uses less digits than its factorization.

161816640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168579 (or 168569 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 33.

The square root of 161816640 is about 12720.7169609264. The cubic root of 161816640 is about 544.9304290736.

The spelling of 161816640 in words is "one hundred sixty-one million, eight hundred sixteen thousand, six hundred forty".