81325663 has 4 divisors (see below), whose sum is σ = 82071880. Its totient is φ = 80579448.

The previous prime is 81325661. The next prime is 81325693. The reversal of 81325663 is 36652318.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36652318 = 2 ⋅18326159.

It is a cyclic number.

It is not a de Polignac number, because 81325663 - 2¹ = 81325661 is a prime.

It is a super-2 number, since 2×81325663² = 13227726924779138, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81325661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 372945 + ... + 373162.

It is an arithmetic number, because the mean of its divisors is an integer number (20517970).

Almost surely, 2^81325663 is an apocalyptic number.

81325663 is a deficient number, since it is larger than the sum of its proper divisors (746217).

81325663 is a wasteful number, since it uses less digits than its factorization.

81325663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 746216.

The product of its digits is 25920, while the sum is 34.

The square root of 81325663 is about 9018.0742401025. The cubic root of 81325663 is about 433.2539565983.

The spelling of 81325663 in words is "eighty-one million, three hundred twenty-five thousand, six hundred sixty-three".