161521633 has 16 divisors (see below), whose sum is σ = 199858176. Its totient is φ = 127114560.

The previous prime is 161521627. The next prime is 161521643. The reversal of 161521633 is 336125161.

161521633 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 161521633 - 2⁵ = 161521601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161521643) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12735 + ... + 22027.

It is an arithmetic number, because the mean of its divisors is an integer number (12491136).

Almost surely, 2^161521633 is an apocalyptic number.

161521633 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

161521633 is a deficient number, since it is larger than the sum of its proper divisors (38336543).

161521633 is a wasteful number, since it uses less digits than its factorization.

161521633 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9504.

The product of its digits is 3240, while the sum is 28.

The square root of 161521633 is about 12709.1161376392. The cubic root of 161521633 is about 544.5990744353.

Adding to 161521633 its reverse (336125161), we get a palindrome (497646794).

The spelling of 161521633 in words is "one hundred sixty-one million, five hundred twenty-one thousand, six hundred thirty-three".