161537731 has 8 divisors (see below), whose sum is σ = 165305664. Its totient is φ = 157783680.

The previous prime is 161537707. The next prime is 161537741. The reversal of 161537731 is 137735161.

161537731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 161537731 - 2¹³ = 161529539 is a prime.

It is a super-2 number, since 2×161537731² = 52188877073256722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161537741) 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, 22251 + ... + 28603.

It is an arithmetic number, because the mean of its divisors is an integer number (20663208).

Almost surely, 2^161537731 is an apocalyptic number.

161537731 is a deficient number, since it is larger than the sum of its proper divisors (3767933).

161537731 is an equidigital number, since it uses as much as digits as its factorization.

161537731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6941.

The product of its digits is 13230, while the sum is 34.

The square root of 161537731 is about 12709.7494467830. The cubic root of 161537731 is about 544.6171662630.

The spelling of 161537731 in words is "one hundred sixty-one million, five hundred thirty-seven thousand, seven hundred thirty-one".