161881031 has 8 divisors (see below), whose sum is σ = 179045664. Its totient is φ = 145389600.

The previous prime is 161881003. The next prime is 161881051. The reversal of 161881031 is 130188161.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161881031 is a prime.

It is a super-2 number, since 2×161881031² = 52410936395245922, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161880985 and 161881003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161881001) 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, 167795 + ... + 168756.

It is an arithmetic number, because the mean of its divisors is an integer number (22380708).

Almost surely, 2^161881031 is an apocalyptic number.

161881031 is a deficient number, since it is larger than the sum of its proper divisors (17164633).

161881031 is a wasteful number, since it uses less digits than its factorization.

161881031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 336601.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 161881031 is about 12723.2476593046. The cubic root of 161881031 is about 545.0027000960.

The spelling of 161881031 in words is "one hundred sixty-one million, eight hundred eighty-one thousand, thirty-one".