72218401 has 4 divisors (see below), whose sum is σ = 72237204. Its totient is φ = 72199600.

The previous prime is 72218387. The next prime is 72218407. The reversal of 72218401 is 10481227.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10481227 = 53 ⋅197759.

It can be written as a sum of positive squares in 2 ways, for example, as 48986001 + 23232400 = 6999^2 + 4820^2 .

It is a cyclic number.

It is not a de Polignac number, because 72218401 - 2⁵ = 72218369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72218407) 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, 1330 + ... + 12091.

It is an arithmetic number, because the mean of its divisors is an integer number (18059301).

Almost surely, 2^72218401 is an apocalyptic number.

It is an amenable number.

72218401 is a deficient number, since it is larger than the sum of its proper divisors (18803).

72218401 is a wasteful number, since it uses less digits than its factorization.

72218401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18802.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 72218401 is about 8498.1410320140. The cubic root of 72218401 is about 416.4369811079.

Adding to 72218401 its reverse (10481227), we get a palindrome (82699628).

The spelling of 72218401 in words is "seventy-two million, two hundred eighteen thousand, four hundred one".