2161737820 has 48 divisors (see below), whose sum is σ = 4956523488. Its totient is φ = 785423360.

The previous prime is 2161737817. The next prime is 2161737827. The reversal of 2161737820 is 287371612.

It is a super-2 number, since 2×2161737820² = 9346220804836704800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 2161737820.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2161737827) 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 15 ways as a sum of consecutive naturals, for example, 311832 + ... + 318688.

It is an arithmetic number, because the mean of its divisors is an integer number (103260906).

Almost surely, 2^2161737820 is an apocalyptic number.

2161737820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2161737820 is an abundant number, since it is smaller than the sum of its proper divisors (2794785668).

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

2161737820 is a wasteful number, since it uses less digits than its factorization.

2161737820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8310 (or 8308 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 37.

The square root of 2161737820 is about 46494.4923619992. The cubic root of 2161737820 is about 1293.0073895805.

The spelling of 2161737820 in words is "two billion, one hundred sixty-one million, seven hundred thirty-seven thousand, eight hundred twenty".