161511621 has 8 divisors (see below), whose sum is σ = 215407680. Its totient is φ = 107644992.

The previous prime is 161511613. The next prime is 161511641. The reversal of 161511621 is 126115161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161511621 - 2³ = 161511613 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161511591 and 161511600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161511641) 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, 16560 + ... + 24438.

It is an arithmetic number, because the mean of its divisors is an integer number (26925960).

Almost surely, 2^161511621 is an apocalyptic number.

It is an amenable number.

161511621 is a deficient number, since it is larger than the sum of its proper divisors (53896059).

161511621 is an equidigital number, since it uses as much as digits as its factorization.

161511621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14715.

The product of its digits is 360, while the sum is 24.

The square root of 161511621 is about 12708.7222410437. The cubic root of 161511621 is about 544.5878217865.

Adding to 161511621 its reverse (126115161), we get a palindrome (287626782).

The spelling of 161511621 in words is "one hundred sixty-one million, five hundred eleven thousand, six hundred twenty-one".