72891145 has 4 divisors (see below), whose sum is σ = 87469380. Its totient is φ = 58312912.

The previous prime is 72891131. The next prime is 72891179. The reversal of 72891145 is 54119827.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54119827 = 3343 ⋅16189.

It can be written as a sum of positive squares in 2 ways, for example, as 49956624 + 22934521 = 7068^2 + 4789^2 .

It is a cyclic number.

It is not a de Polignac number, because 72891145 - 2²¹ = 70793993 is a prime.

It is a super-2 number, since 2×72891145² = 10626238038822050, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7289110 + ... + 7289119.

It is an arithmetic number, because the mean of its divisors is an integer number (21867345).

Almost surely, 2^72891145 is an apocalyptic number.

It is an amenable number.

72891145 is a deficient number, since it is larger than the sum of its proper divisors (14578235).

72891145 is a wasteful number, since it uses less digits than its factorization.

72891145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14578234.

The product of its digits is 20160, while the sum is 37.

The square root of 72891145 is about 8537.6311117312. The cubic root of 72891145 is about 417.7260802377.

The spelling of 72891145 in words is "seventy-two million, eight hundred ninety-one thousand, one hundred forty-five".