161660400 has 240 divisors, whose sum is σ = 581950848. Its totient is φ = 38016000.

The previous prime is 161660377. The next prime is 161660423. The reversal of 161660400 is 4066161.

It is an interprime number because it is at equal distance from previous prime (161660377) and next prime (161660423).

It is a tau number, because it is divible by the number of its divisors (240).

It is a super-2 number, since 2×161660400² = 52268169856320000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 488235 + ... + 488565.

Almost surely, 2^161660400 is an apocalyptic number.

161660400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161660400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (290975424).

161660400 is an abundant number, since it is smaller than the sum of its proper divisors (420290448).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161660400 is a wasteful number, since it uses less digits than its factorization.

161660400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400 (or 389 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 161660400 is about 12714.5743145416. The cubic root of 161660400 is about 544.7549890470.

The spelling of 161660400 in words is "one hundred sixty-one million, six hundred sixty thousand, four hundred".