161855772 has 24 divisors (see below), whose sum is σ = 406714896. Its totient is φ = 49801728.

The previous prime is 161855747. The next prime is 161855887. The reversal of 161855772 is 277558161.

161855772 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-3 number, since 3×161855772³ (a number of 26 digits) contains 333 as substring.

It is a congruent 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, 518613 + ... + 518924.

It is an arithmetic number, because the mean of its divisors is an integer number (16946454).

Almost surely, 2^161855772 is an apocalyptic number.

161855772 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

161855772 is an abundant number, since it is smaller than the sum of its proper divisors (244859124).

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

161855772 is a wasteful number, since it uses less digits than its factorization.

161855772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1037557 (or 1037555 counting only the distinct ones).

The product of its digits is 117600, while the sum is 42.

The square root of 161855772 is about 12722.2549887982. The cubic root of 161855772 is about 544.9743522425.

The spelling of 161855772 in words is "one hundred sixty-one million, eight hundred fifty-five thousand, seven hundred seventy-two".