161660401 has 16 divisors (see below), whose sum is σ = 190840320. Its totient is φ = 134069760.

The previous prime is 161660377. The next prime is 161660423. The reversal of 161660401 is 104066161.

It is a cyclic number.

It is not a de Polignac number, because 161660401 - 2⁷ = 161660273 is a prime.

It is a super-2 number, since 2×161660401² = 52268170502961602, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161660101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26521 + ... + 32041.

It is an arithmetic number, because the mean of its divisors is an integer number (11927520).

Almost surely, 2^161660401 is an apocalyptic number.

It is an amenable number.

161660401 is a deficient number, since it is larger than the sum of its proper divisors (29179919).

161660401 is an equidigital number, since it uses as much as digits as its factorization.

161660401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5664.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 161660401 is about 12714.5743538665. The cubic root of 161660401 is about 544.7549901703.

The spelling of 161660401 in words is "one hundred sixty-one million, six hundred sixty thousand, four hundred one".