181821740 has 24 divisors (see below), whose sum is σ = 383942832. Its totient is φ = 72325440.

The previous prime is 181821733. The next prime is 181821767. The reversal of 181821740 is 47128181.

It is a junction number, because it is equal to n+sod(n) for n = 181821697 and 181821706.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21494 + ... + 28733.

It is an arithmetic number, because the mean of its divisors is an integer number (15997618).

Almost surely, 2^181821740 is an apocalyptic number.

181821740 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

181821740 is an abundant number, since it is smaller than the sum of its proper divisors (202121092).

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

181821740 is a wasteful number, since it uses less digits than its factorization.

181821740 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50417 (or 50415 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 32.

The square root of 181821740 is about 13484.1291895324. The cubic root of 181821740 is about 566.5200304935.

The spelling of 181821740 in words is "one hundred eighty-one million, eight hundred twenty-one thousand, seven hundred forty".