161617213 has 4 divisors (see below), whose sum is σ = 162646780. Its totient is φ = 160587648.

The previous prime is 161617207. The next prime is 161617217. The reversal of 161617213 is 312716161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 17665209 + 143952004 = 4203^2 + 11998^2 .

It is a cyclic number.

It is not a de Polignac number, because 161617213 - 2¹⁷ = 161486141 is a prime.

It is a super-2 number, since 2×161617213² = 52240247075774738, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161617217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 514548 + ... + 514861.

It is an arithmetic number, because the mean of its divisors is an integer number (40661695).

Almost surely, 2^161617213 is an apocalyptic number.

It is an amenable number.

161617213 is a deficient number, since it is larger than the sum of its proper divisors (1029567).

161617213 is a wasteful number, since it uses less digits than its factorization.

161617213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1029566.

The product of its digits is 1512, while the sum is 28.

The square root of 161617213 is about 12712.8758744825. The cubic root of 161617213 is about 544.7064749417.

The spelling of 161617213 in words is "one hundred sixty-one million, six hundred seventeen thousand, two hundred thirteen".