181213479720 has 1536 divisors, whose sum is σ = 810819072000. Its totient is φ = 35602882560.

The previous prime is 181213479703. The next prime is 181213479721. The reversal of 181213479720 is 27974312181.

181213479720 is a `hidden beast` number, since 181 + 21 + 347 + 97 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (181213479721) by changing a digit.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 618475894 + ... + 618476186.

It is an arithmetic number, because the mean of its divisors is an integer number (527877000).

Almost surely, 2^181213479720 is an apocalyptic number.

181213479720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181213479720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (405409536000).

181213479720 is an abundant number, since it is smaller than the sum of its proper divisors (629605592280).

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

181213479720 is a wasteful number, since it uses less digits than its factorization.

181213479720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400 (or 383 counting only the distinct ones).

The product of its (nonzero) digits is 169344, while the sum is 45.

The spelling of 181213479720 in words is "one hundred eighty-one billion, two hundred thirteen million, four hundred seventy-nine thousand, seven hundred twenty".