161881751 has 8 divisors (see below), whose sum is σ = 169082880. Its totient is φ = 154694232.

The previous prime is 161881747. The next prime is 161881757. The reversal of 161881751 is 157188161.

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

It is a cyclic number.

It is not a de Polignac number, because 161881751 - 2² = 161881747 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161881757) 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, 26666 + ... + 32168.

It is an arithmetic number, because the mean of its divisors is an integer number (21135360).

Almost surely, 2^161881751 is an apocalyptic number.

161881751 is a deficient number, since it is larger than the sum of its proper divisors (7201129).

161881751 is a wasteful number, since it uses less digits than its factorization.

161881751 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6805.

The product of its digits is 13440, while the sum is 38.

The square root of 161881751 is about 12723.2759539358. The cubic root of 161881751 is about 545.0035080996.

The spelling of 161881751 in words is "one hundred sixty-one million, eight hundred eighty-one thousand, seven hundred fifty-one".