81572847 has 4 divisors (see below), whose sum is σ = 108763800. Its totient is φ = 54381896.

The previous prime is 81572839. The next prime is 81572857. The reversal of 81572847 is 74827518.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81572847 - 2³ = 81572839 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81572799 and 81572808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81572837) 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, 13595472 + ... + 13595477.

It is an arithmetic number, because the mean of its divisors is an integer number (27190950).

Almost surely, 2^81572847 is an apocalyptic number.

81572847 is a deficient number, since it is larger than the sum of its proper divisors (27190953).

81572847 is a wasteful number, since it uses less digits than its factorization.

81572847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27190952.

The product of its digits is 125440, while the sum is 42.

The square root of 81572847 is about 9031.7687636476. The cubic root of 81572847 is about 433.6924615906.

The spelling of 81572847 in words is "eighty-one million, five hundred seventy-two thousand, eight hundred forty-seven".