161520621 has 16 divisors (see below), whose sum is σ = 228412224. Its totient is φ = 101176064.

The previous prime is 161520613. The next prime is 161520629. The reversal of 161520621 is 126025161.

It is an interprime number because it is at equal distance from previous prime (161520613) and next prime (161520629).

It is a cyclic number.

It is not a de Polignac number, because 161520621 - 2³ = 161520613 is a prime.

It is a super-2 number, since 2×161520621² = 52177822016451282, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161520591 and 161520600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161520629) 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, 32515 + ... + 37151.

It is an arithmetic number, because the mean of its divisors is an integer number (14275764).

Almost surely, 2^161520621 is an apocalyptic number.

It is an amenable number.

161520621 is a deficient number, since it is larger than the sum of its proper divisors (66891603).

161520621 is a wasteful number, since it uses less digits than its factorization.

161520621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5340.

The product of its (nonzero) digits is 720, while the sum is 24.

The square root of 161520621 is about 12709.0763236358. The cubic root of 161520621 is about 544.5979370532.

Adding to 161520621 its reverse (126025161), we get a palindrome (287545782).

The spelling of 161520621 in words is "one hundred sixty-one million, five hundred twenty thousand, six hundred twenty-one".