81525247 has 2 divisors, whose sum is σ = 81525248. Its totient is φ = 81525246.

The previous prime is 81525211. The next prime is 81525263. The reversal of 81525247 is 74252518.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81525247 - 2²³ = 73136639 is a prime.

It is a super-2 number, since 2×81525247² = 13292731796822018, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81525277) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40762623 + 40762624.

It is an arithmetic number, because the mean of its divisors is an integer number (40762624).

Almost surely, 2^81525247 is an apocalyptic number.

81525247 is a deficient number, since it is larger than the sum of its proper divisors (1).

81525247 is an equidigital number, since it uses as much as digits as its factorization.

81525247 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 22400, while the sum is 34.

The square root of 81525247 is about 9029.1332363633. The cubic root of 81525247 is about 433.6080880168.

It can be divided in two parts, 815 and 25247, that added together give a palindrome (26062).

The spelling of 81525247 in words is "eighty-one million, five hundred twenty-five thousand, two hundred forty-seven".