72181778 has 8 divisors (see below), whose sum is σ = 110790768. Its totient is φ = 35251524.

The previous prime is 72181777. The next prime is 72181787. The reversal of 72181778 is 87718127.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (72181777) 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, 419576 + ... + 419747.

It is an arithmetic number, because the mean of its divisors is an integer number (13848846).

Almost surely, 2^72181778 is an apocalyptic number.

72181778 is a deficient number, since it is larger than the sum of its proper divisors (38608990).

72181778 is a wasteful number, since it uses less digits than its factorization.

72181778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 839368.

The product of its digits is 43904, while the sum is 41.

The square root of 72181778 is about 8495.9859933971. The cubic root of 72181778 is about 416.3665754583.

The spelling of 72181778 in words is "seventy-two million, one hundred eighty-one thousand, seven hundred seventy-eight".