161212321 has 8 divisors (see below), whose sum is σ = 170580320. Its totient is φ = 151932672.

The previous prime is 161212301. The next prime is 161212327. The reversal of 161212321 is 123212161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161212321 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161212327) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 18315 + ... + 25648.

It is an arithmetic number, because the mean of its divisors is an integer number (21322540).

Almost surely, 2^161212321 is an apocalyptic number.

It is an amenable number.

161212321 is a deficient number, since it is larger than the sum of its proper divisors (9367999).

161212321 is a wasteful number, since it uses less digits than its factorization.

161212321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44175.

The product of its digits is 144, while the sum is 19.

The square root of 161212321 is about 12696.9414033459. The cubic root of 161212321 is about 544.2512187176.

Adding to 161212321 its reverse (123212161), we get a palindrome (284424482).

The spelling of 161212321 in words is "one hundred sixty-one million, two hundred twelve thousand, three hundred twenty-one".