161906401 has 4 divisors (see below), whose sum is σ = 161950000. Its totient is φ = 161862804.

The previous prime is 161906389. The next prime is 161906411. The reversal of 161906401 is 104609161.

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.

It is a cyclic number.

It is not a de Polignac number, because 161906401 - 2⁵ = 161906369 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 161906401.

It is not an unprimeable number, because it can be changed into a prime (161906411) 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, 15651 + ... + 23848.

It is an arithmetic number, because the mean of its divisors is an integer number (40487500).

Almost surely, 2^161906401 is an apocalyptic number.

It is an amenable number.

161906401 is a deficient number, since it is larger than the sum of its proper divisors (43599).

161906401 is an equidigital number, since it uses as much as digits as its factorization.

161906401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43598.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 161906401 is about 12724.2446141215. The cubic root of 161906401 is about 545.0311695553.

The spelling of 161906401 in words is "one hundred sixty-one million, nine hundred six thousand, four hundred one".