73218991 has 8 divisors (see below), whose sum is σ = 73932624. Its totient is φ = 72508800.

The previous prime is 73218953. The next prime is 73219019. The reversal of 73218991 is 19981237.

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

It is a cyclic number.

It is not a de Polignac number, because 73218991 - 2⁷ = 73218863 is a prime.

It is a super-2 number, since 2×73218991² = 10722041286116162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (73218091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 62376 + ... + 63538.

It is an arithmetic number, because the mean of its divisors is an integer number (9241578).

Almost surely, 2^73218991 is an apocalyptic number.

73218991 is a deficient number, since it is larger than the sum of its proper divisors (713633).

73218991 is a wasteful number, since it uses less digits than its factorization.

73218991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1721.

The product of its digits is 27216, while the sum is 40.

The square root of 73218991 is about 8556.8096274254. The cubic root of 73218991 is about 418.3514191779.

The spelling of 73218991 in words is "seventy-three million, two hundred eighteen thousand, nine hundred ninety-one".