72805181 has 4 divisors (see below), whose sum is σ = 72828864. Its totient is φ = 72781500.

The previous prime is 72805177. The next prime is 72805223. The reversal of 72805181 is 18150827.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72805181 - 2² = 72805177 is a prime.

It is a super-2 number, since 2×72805181² = 10601188760885522, 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 (72805121) 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, 6395 + ... + 13656.

It is an arithmetic number, because the mean of its divisors is an integer number (18207216).

Almost surely, 2^72805181 is an apocalyptic number.

It is an amenable number.

72805181 is a deficient number, since it is larger than the sum of its proper divisors (23683).

72805181 is a wasteful number, since it uses less digits than its factorization.

72805181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23682.

The product of its (nonzero) digits is 4480, while the sum is 32.

The square root of 72805181 is about 8532.5952089619. The cubic root of 72805181 is about 417.5618008840.

The spelling of 72805181 in words is "seventy-two million, eight hundred five thousand, one hundred eighty-one".