161261531 has 8 divisors (see below), whose sum is σ = 170380800. Its totient is φ = 152205480.

The previous prime is 161261501. The next prime is 161261539. The reversal of 161261531 is 135162161.

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 161261531 - 2¹⁰ = 161260507 is a prime.

It is a super-2 number, since 2×161261531² = 52010562760927922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161261531.

It is not an unprimeable number, because it can be changed into a prime (161261539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10511 + ... + 20808.

It is an arithmetic number, because the mean of its divisors is an integer number (21297600).

Almost surely, 2^161261531 is an apocalyptic number.

161261531 is a deficient number, since it is larger than the sum of its proper divisors (9119269).

161261531 is a wasteful number, since it uses less digits than its factorization.

161261531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31609.

The product of its digits is 1080, while the sum is 26.

The square root of 161261531 is about 12698.8791237652. The cubic root of 161261531 is about 544.3065905768.

The spelling of 161261531 in words is "one hundred sixty-one million, two hundred sixty-one thousand, five hundred thirty-one".