1661016220 has 24 divisors (see below), whose sum is σ = 3506404608. Its totient is φ = 660926400.

The previous prime is 1661016199. The next prime is 1661016221. The reversal of 1661016220 is 226101661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661016221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 213591 + ... + 221230.

It is an arithmetic number, because the mean of its divisors is an integer number (146100192).

Almost surely, 2^1661016220 is an apocalyptic number.

1661016220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1661016220 is an abundant number, since it is smaller than the sum of its proper divisors (1845388388).

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

1661016220 is a wasteful number, since it uses less digits than its factorization.

1661016220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 435021 (or 435019 counting only the distinct ones).

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

The square root of 1661016220 is about 40755.5667363368. The cubic root of 1661016220 is about 1184.2897154055.

Adding to 1661016220 its reverse (226101661), we get a palindrome (1887117881).

The spelling of 1661016220 in words is "one billion, six hundred sixty-one million, sixteen thousand, two hundred twenty".