161139640 has 16 divisors (see below), whose sum is σ = 362564280. Its totient is φ = 64455840.

The previous prime is 161139637. The next prime is 161139647. The reversal of 161139640 is 46931161.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161139647) 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, 2014206 + ... + 2014285.

Almost surely, 2^161139640 is an apocalyptic number.

161139640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161139640 is an abundant number, since it is smaller than the sum of its proper divisors (201424640).

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

161139640 is a wasteful number, since it uses less digits than its factorization.

161139640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4028502 (or 4028498 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 31.

The square root of 161139640 is about 12694.0789346845. The cubic root of 161139640 is about 544.1694163081.

The spelling of 161139640 in words is "one hundred sixty-one million, one hundred thirty-nine thousand, six hundred forty".