161612778 has 16 divisors (see below), whose sum is σ = 342239040. Its totient is φ = 50702016.

The previous prime is 161612723. The next prime is 161612797. The reversal of 161612778 is 877216161.

It is a super-2 number, since 2×161612778² = 52237380025754568, which contains 22 as substring.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 792118 + ... + 792321.

It is an arithmetic number, because the mean of its divisors is an integer number (21389940).

Almost surely, 2^161612778 is an apocalyptic number.

161612778 is an abundant number, since it is smaller than the sum of its proper divisors (180626262).

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

161612778 is a wasteful number, since it uses less digits than its factorization.

161612778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1584461.

The product of its digits is 28224, while the sum is 39.

The square root of 161612778 is about 12712.7014438317. The cubic root of 161612778 is about 544.7014923963.

The spelling of 161612778 in words is "one hundred sixty-one million, six hundred twelve thousand, seven hundred seventy-eight".