72047891 has 4 divisors (see below), whose sum is σ = 75180432. Its totient is φ = 68915352.

The previous prime is 72047879. The next prime is 72047897. The reversal of 72047891 is 19874027.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19874027 = 863 ⋅23029.

It is a cyclic number.

It is not a de Polignac number, because 72047891 - 2²² = 67853587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72047897) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1566236 + ... + 1566281.

It is an arithmetic number, because the mean of its divisors is an integer number (18795108).

Almost surely, 2^72047891 is an apocalyptic number.

72047891 is a deficient number, since it is larger than the sum of its proper divisors (3132541).

72047891 is a wasteful number, since it uses less digits than its factorization.

72047891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3132540.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 72047891 is about 8488.1029093667. The cubic root of 72047891 is about 416.1089824026.

The spelling of 72047891 in words is "seventy-two million, forty-seven thousand, eight hundred ninety-one".