161221003 has 2 divisors, whose sum is σ = 161221004. Its totient is φ = 161221002.

The previous prime is 161220989. The next prime is 161221069. The reversal of 161221003 is 300122161.

It is a weak prime.

It is an emirp because it is prime and its reverse (300122161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161221003 - 2⁵ = 161220971 is a prime.

It is not a weakly prime, because it can be changed into another prime (161221103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80610501 + 80610502.

It is an arithmetic number, because the mean of its divisors is an integer number (80610502).

Almost surely, 2^161221003 is an apocalyptic number.

161221003 is a deficient number, since it is larger than the sum of its proper divisors (1).

161221003 is an equidigital number, since it uses as much as digits as its factorization.

161221003 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 16.

The square root of 161221003 is about 12697.2832921062. The cubic root of 161221003 is about 544.2609886579.

Adding to 161221003 its reverse (300122161), we get a palindrome (461343164).

The spelling of 161221003 in words is "one hundred sixty-one million, two hundred twenty-one thousand, three".