161008621 has 2 divisors, whose sum is σ = 161008622. Its totient is φ = 161008620.

The previous prime is 161008619. The next prime is 161008643. The reversal of 161008621 is 126800161.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 146652100 + 14356521 = 12110^2 + 3789^2 .

It is a cyclic number.

It is not a de Polignac number, because 161008621 - 2¹ = 161008619 is a prime.

Together with 161008619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161008021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80504310 + 80504311.

It is an arithmetic number, because the mean of its divisors is an integer number (80504311).

Almost surely, 2^161008621 is an apocalyptic number.

It is an amenable number.

161008621 is a deficient number, since it is larger than the sum of its proper divisors (1).

161008621 is an equidigital number, since it uses as much as digits as its factorization.

161008621 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 161008621 is about 12688.9172508926. The cubic root of 161008621 is about 544.0218923662.

Adding to 161008621 its reverse (126800161), we get a palindrome (287808782).

The spelling of 161008621 in words is "one hundred sixty-one million, eight thousand, six hundred twenty-one".