72811881 has 6 divisors (see below), whose sum is σ = 105172730. Its totient is φ = 48541248.

The previous prime is 72811873. The next prime is 72811897. The reversal of 72811881 is 18811827.

72811881 is nontrivially palindromic in base 15.

It can be written as a sum of positive squares in only one way, i.e., 64256256 + 8555625 = 8016^2 + 2925^2 .

It is not a de Polignac number, because 72811881 - 2³ = 72811873 is a prime.

It is a super-2 number, since 2×72811881² = 10603140029516322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72811861) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4045096 + ... + 4045113.

Almost surely, 2^72811881 is an apocalyptic number.

It is an amenable number.

72811881 is a deficient number, since it is larger than the sum of its proper divisors (32360849).

72811881 is a wasteful number, since it uses less digits than its factorization.

72811881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8090215 (or 8090212 counting only the distinct ones).

The product of its digits is 7168, while the sum is 36.

The square root of 72811881 is about 8532.9878120152. The cubic root of 72811881 is about 417.5746093967.

The spelling of 72811881 in words is "seventy-two million, eight hundred eleven thousand, eight hundred eighty-one".