161913553 has 2 divisors, whose sum is σ = 161913554. Its totient is φ = 161913552.

The previous prime is 161913509. The next prime is 161913599. The reversal of 161913553 is 355319161.

It is a happy number.

161913553 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 158180929 + 3732624 = 12577^2 + 1932^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161913553 is a prime.

It is not a weakly prime, because it can be changed into another prime (161913503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80956776 + 80956777.

It is an arithmetic number, because the mean of its divisors is an integer number (80956777).

Almost surely, 2^161913553 is an apocalyptic number.

It is an amenable number.

161913553 is a deficient number, since it is larger than the sum of its proper divisors (1).

161913553 is an equidigital number, since it uses as much as digits as its factorization.

161913553 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12150, while the sum is 34.

The square root of 161913553 is about 12724.5256493120. The cubic root of 161913553 is about 545.0391947796.

The spelling of 161913553 in words is "one hundred sixty-one million, nine hundred thirteen thousand, five hundred fifty-three".