161591020 has 12 divisors (see below), whose sum is σ = 339341184. Its totient is φ = 64636400.

The previous prime is 161590973. The next prime is 161591021. The reversal of 161591020 is 20195161.

It is a super-2 number, since 2×161591020² = 52223315489280800, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161591021) 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, 4039756 + ... + 4039795.

It is an arithmetic number, because the mean of its divisors is an integer number (28278432).

Almost surely, 2^161591020 is an apocalyptic number.

161591020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161591020 is an abundant number, since it is smaller than the sum of its proper divisors (177750164).

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

161591020 is a wasteful number, since it uses less digits than its factorization.

161591020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8079560 (or 8079558 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 25.

The square root of 161591020 is about 12711.8456567093. The cubic root of 161591020 is about 544.6770468313.

The spelling of 161591020 in words is "one hundred sixty-one million, five hundred ninety-one thousand, twenty".