161801431 has 8 divisors (see below), whose sum is σ = 182204928. Its totient is φ = 142347000.

The previous prime is 161801413. The next prime is 161801443. The reversal of 161801431 is 134108161.

It is a happy number.

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 161801431 - 2¹⁷ = 161670359 is a prime.

It is a super-2 number, since 2×161801431² = 52359406147295522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 161801396 and 161801405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161801831) 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, 236905 + ... + 237586.

It is an arithmetic number, because the mean of its divisors is an integer number (22775616).

Almost surely, 2^161801431 is an apocalyptic number.

161801431 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

161801431 is a deficient number, since it is larger than the sum of its proper divisors (20403497).

161801431 is a wasteful number, since it uses less digits than its factorization.

161801431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474533.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 161801431 is about 12720.1191425238. The cubic root of 161801431 is about 544.9133560322.

Adding to 161801431 its reverse (134108161), we get a palindrome (295909592).

The spelling of 161801431 in words is "one hundred sixty-one million, eight hundred one thousand, four hundred thirty-one".