161217857 has 4 divisors (see below), whose sum is σ = 161513136. Its totient is φ = 160922580.

The previous prime is 161217827. The next prime is 161217911. The reversal of 161217857 is 758712161.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 758712161 = 19 ⋅39932219.

It is a cyclic number.

It is not a de Polignac number, because 161217857 - 2¹² = 161213761 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161217857.

It is not an unprimeable number, because it can be changed into a prime (161217827) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 146819 + ... + 147912.

It is an arithmetic number, because the mean of its divisors is an integer number (40378284).

Almost surely, 2^161217857 is an apocalyptic number.

It is an amenable number.

161217857 is a deficient number, since it is larger than the sum of its proper divisors (295279).

161217857 is an equidigital number, since it uses as much as digits as its factorization.

161217857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 295278.

The product of its digits is 23520, while the sum is 38.

The square root of 161217857 is about 12697.1594067335. The cubic root of 161217857 is about 544.2574484736.

The spelling of 161217857 in words is "one hundred sixty-one million, two hundred seventeen thousand, eight hundred fifty-seven".