161565426 has 48 divisors (see below), whose sum is σ = 383067360. Its totient is φ = 48807360.

The previous prime is 161565419. The next prime is 161565427. The reversal of 161565426 is 624565161.

161565426 is a `hidden beast` number, since 1 + 61 + 56 + 542 + 6 = 666.

It is a super-2 number, since 2×161565426² = 52206773757122952, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161565427) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 73966 + ... + 76118.

It is an arithmetic number, because the mean of its divisors is an integer number (7980570).

Almost surely, 2^161565426 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161565426, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (191533680).

161565426 is an abundant number, since it is smaller than the sum of its proper divisors (221501934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161565426 is a wasteful number, since it uses less digits than its factorization.

161565426 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2551 (or 2548 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 161565426 is about 12710.8389180258. The cubic root of 161565426 is about 544.6482886318.

The spelling of 161565426 in words is "one hundred sixty-one million, five hundred sixty-five thousand, four hundred twenty-six".