81624047 has 2 divisors, whose sum is σ = 81624048. Its totient is φ = 81624046.

The previous prime is 81624017. The next prime is 81624061. The reversal of 81624047 is 74042618.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81624047 - 2²⁰ = 80575471 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81624017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40812023 + 40812024.

It is an arithmetic number, because the mean of its divisors is an integer number (40812024).

Almost surely, 2^81624047 is an apocalyptic number.

81624047 is a deficient number, since it is larger than the sum of its proper divisors (1).

81624047 is an equidigital number, since it uses as much as digits as its factorization.

81624047 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 81624047 is about 9034.6027582844. The cubic root of 81624047 is about 433.7831797267.

The spelling of 81624047 in words is "eighty-one million, six hundred twenty-four thousand, forty-seven".